LONDON -- Zara Phillips, Queen Elizabeth II's granddaughter, raced through the difficult and dangerous cross-country portion of her first Olympic equestrian eventing competition Monday, finishing clean and well under the pace time as she was cheered on wildly by thousands of fans, royal and not.

"The crowd was unbelievable!" Phillips said after she finished. "I hope I didn't take any heads off on the way cutting corners."

Princes William and Harry watched her from the main equestrian arena, joined by William's wife, Kate, and Camilla, the wife of Prince Charles. Seated alongside them were Princess Beatrice and Princess Eugenie, the daughters of Prince Andrew.

Phillips' mother, Princess Anne, watched from the grounds of the twisty, hilly 5.7-kilometer (3.5-mile) course dotted with 28 obstacles.

Phillips said her time of 9 minutes, 55.11 seconds – well off the 10-minute, 3-second time limit – was particularly good given that her horse, High Kingdom, lost a shoe during the ride.

"He did amazing," she said. "He really grew up and stepped up to the plate." She said the only drawback to the raucous cheers from the crowd was that she couldn't hear the timer on her wrist ticking.

The thrilling cross country portion of the three-discipline eventing competition is designed to test horse and rider endurance – and guts – and the course up and down the hills of Greenwich Park fit the bill. There were razor-sharp turns, blind 2-meter (yard) drops and tricky combination jumps – each one designed with a very British story behind it.

The first few horses out Monday seemed to handle the course relatively well, but as the afternoon wore on more than a half-dozen riders fell from their mounts and several horses slipped on the tight turns.

"He was slipping in the warmup so I changed to longer studs for the course," said American Karen O'Connor of Mr. Medicott, a horse purchased for her from the gold medal-winning German team four years ago. O'Connor earned 5.6 penalties for exceeding the time limit and was in a provisional eighth place about halfway through the competition.

Germany's Ingrid Klimke, part of the gold-winning German eventing team in 2008, was in provisional first place riding Butts Abraxxas.

Several of the riders who fell wore protective vests that inflated much like airbags upon impact.

Thousands of people lined the narrow course to watch the horses, getting an unusually close view of them and enjoying a festive picnic atmosphere on the grass.

The royals were watching the competition on big screens inside the main arena; the course comes into the arena itself for the 16th obstacle, a combination jump that's a miniature version of the Tower of London.

On Sunday, Phillips' grandfather, the Duke of Edinburgh, joined her mother in the VIP stands to watch her earn a respectable score in the dressage portion of her Olympic debut. With 46.10 penalty points for a slight mistake, Phillips landed in 24th place out of 74 riders. After cross-country, she'll compete in show jumping Tuesday, the final portion of eventing.

The course included English rose gardens to jump over, a tricky No. 3 combination jump that saw several refusals Monday, and even a swampy scene from the British children's classic "The Wind in the Willows." One tough jump depicts the Prime Meridian Line that runs nearby; another is a crescent moon, a nod to the Royal Observatory on the park grounds.

The course starts with a diamond-framed hedge in honor of Queen Elizabeth II's recently celebrated Diamond Jubilee. It ends with a giant, upside down horseshoe flanked by two equine sculptures made entirely of recycled horseshoes.

Phillips, a former world and European eventing champion who is 14th in line to the British throne, said she was thrilled to be representing Britain on her home soil – literally. Greenwich Park is the oldest royal park in London. The main equestrian arena sits in front of Queen's House, a 17th-century building designed as a summer palace for Queen Anne of Denmark, the wife of James I.

Her mother, Anne, competed at the 1976 Montreal Olympics, but her horse fell going over a jump during the cross country event. Phillips' father, Capt. Mark Phillips, fared better, winning team gold at Munich in 1972 and silver in Seoul 16 years later.

After the dressage portion Sunday, Germany was in the lead with 119.0 penalty points followed by Australia with 122.1 and Britain with 127.

___

Margaret Freeman contributed to this report.

___

Also on HuffPost:

Loading Slideshow...
  • An Kae Um

    North Korea's An Kae Um competes with Cuba's Acosta Bermoy, right, during the gold medal match in the women's 52-kg judo competition at the 2012 Summer Olympics, Sunday, July 29, 2012, in London. (AP Photo/Paul Sancya)

  • Om Yun Chol

    North Korea's Om Yun Chol celebrates winning the gold medal in the men's 56-kg weightlifting competition at the 2012 Summer Olympics, Sunday, July 29, 2012, in London.(AP Photo/Stephen Pond, PA)

  • An Kae Um

    North Korea's An Kum Ae holds her gold medal in the women's 52-kg judo competition at the 2012 Summer Olympics, Sunday, July 29, 2012, in London. (AP Photo/Paul Sancya)

  • Wang Xin

    China's Wang Xin plays against United States' Rena Wang at a women's singles match of the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Saurabh Das)

  • Olympic Cauldron

    The Olympic cauldron is lit after it was moved from the infield to its resting position at the Olympic Stadium during the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Jae C. Hong)

  • Austin Playfoot

    Torchbearer Austin Playfoot, far left, poses after lighting the Olympic cauldron at the Olympic Stadium during the 2012 Summer Olympics, Monday, July 30, 2012, in London. The cauldron was moved from the infield to its resting position at the stadium. (AP Photo/Jae C. Hong)

  • Wang Xin

    China's Wang Xin plays against United States' Rena Wang at a women's singles match of the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Saurabh Das)

  • Marti Malloy

    Marti Malloy of the United States competes with Telma Monteiro of Portugal, top, during the women's 57-kg judo competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Paul Sancya)

  • Natacha Rigobert

    Natacha Rigobert, left, and Nioun Li Yuk Lo of Mauritius go for a ball during a beach volleyball match against the Chech Republic at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Dave Martin)

  • Federica Pellegrini

    Italy's Federica Pellegrini looks at her time after competing in a women's 200-meter freestyle swimming heat at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Monday, July 30, 2012. (AP Photo/Mark J. Terrill)

  • Missy Franklin

    United States' Missy Franklin, top, and Italy's Federica Pellegrini compete in a women's 200-meter freestyle swimming heat at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Monday, July 30, 2012. (AP Photo/David J. Phillip)

  • Camille Muffat

    France's Camille Muffat competes in a women's 200-meter freestyle swimming heat at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Monday, July 30, 2012. (AP Photo/David J. Phillip)

  • Bahar Toksoy

    Turkey's Bahar Toksoy (8) spikes the ball to China during a women's volleyball preliminary match at the 2012 Summer Olympics Monday, July 30, 2012, in London. (AP Photo/Chris O'Meara)

  • Michael Phelps

    United States' Michael Phelps reacts after competing in a men's 200-meter butterfly swimming heat at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Monday, July 30, 2012. (AP Photo/Matt Slocum)

  • Pia Lionetti

    Italy's Pia Lionetti shoots during an elimination round of the individual archery competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Marcio Jose Sanchez)

  • Sarah Clark

    Sarah Clark of Britain competes with Automne Pavia of France in the women's 57-kg judo competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Paul Sancya)

  • Julio Cesar Salamanca Pineda

    Julio Cesar Salamanca Pineda of El Salvador competes during the mens 62-kg weightlifting competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Mike Groll)

  • Manuel Minginfel

    Manuel Minginfel off Micronesia reacts while competing during the men's 62-kg, group B, weightlifting competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Hassan Ammar)

  • Nadine Zumkehr

    Nadine Zumkehr from Switzerland dives for a ball during the Beach Volleyball match against China at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Petr David Josek)

  • Manuel Minginfel

    Manuel Minginfel off Micronesia competes during the mens 62-kg weightlifting competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Mike Groll)

  • Manuel Minginfel

    Manuel Minginfel off Micronesia competes during the mens 62-kg weightlifting competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Mike Groll)

  • Volleyball

    A fan cheering for Turkey celebrates as he team scores a point against China during a women's volleyball preliminary match at the 2012 Summer Olympics Monday, July 30, 2012, in London. (AP Photo/Chris O'Meara)

  • Imke Duplitzer

    Germany's Imke Duplitzer, right, faces Venezuela's Maria Martinez in a women's individual epee fencing round of 64 at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Andrew Medichini)

  • Daniel Williams

    Daniel Williams of Britain reacts after losing his match during the men's 73-kg judo competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Paul Sancya)

  • Michael Phelps

    United States' Michael Phelps prepares for a men's 200-meter butterfly swimming heat at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Monday, July 30, 2012. (AP Photo/David J. Phillip, Pool)

  • China Celebrates

    China players celebrate their 3-1 win over Turkey during a women's volleyball preliminary match at the 2012 Summer Olympics Monday, July 30, 2012, in London. (AP Photo/Chris O'Meara)

  • Corinna Lawrence

    Britain's Corinna Lawrence participates in a women's individual epee fencing round of 64 against Chile's Caterin Bravo Aranguiz at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Andrew Medichini)

  • Michael Phelps

    United States' Michael Phelps, left, starts in a men's 200-meter butterfly swimming heat at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Monday, July 30, 2012. (AP Photo/David J. Phillip, Pool)

  • Norio Sasaki

    Japan team coach Norio Sasaki, left, talks to players during a women's soccer training session in Cardiff, Wales, at the 2012 London Summer Olympics, Monday, July 30, 2012. Japan will play in the group F against South Africa on Tuesday. (AP Photo/Luca Bruno)

  • Niluka Karunaratne

    Sri Lanka's Niluka Karunaratne reacts after winning against Japan's Kenichi Tago at a men's singles badminton match of the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Saurabh Das)

  • Nadine Zumkehr

    Nadine Zumkehr of Switzerland reacts during a beach volleyball match against China at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Dave Martin)

  • You Hyo-sik

    South Korea's You Hyo-sik celebrates after scoring a goal against New Zealand during their men's hockey preliminary round match at the 2012 at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Eranga Jayawardena)

  • Eton Dorney

    Fans rest on the grass at the rowing venue in Eton Dorney, near Windsor, England, at the 2012 Summer Olympics, Monday, July 30, 2012. (AP Photo/Natacha Pisarenko)

  • You Hyo-sik

    South Korea's You Hyo-sik, right, celebrates after scoring a goal against New Zealand during their men's hockey preliminary round match at the 2012 at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Eranga Jayawardena)

  • Paul Drinkhall

    Paul Drinkhall of Great Britain serves against Dimitrij Ovtcharov of Germany during their men's table tennis match at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Sergei Grits

  • Miyuki Maeda

    Japan's Miyuki Maeda, right, and Satoko Suetsuna, play against China's Tian Qing, and Zhao Yunlei, unseen, at a women's doubles badminton match of the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Saurabh Das)

  • Im Dung-hyun

    South Korea's Im Dung-hyun shoots during an elimination round of the individual archery competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Marcio Jose Sanchez)

  • Eton Dorney

    Fans waving British flags cheer at the rowing venue in Eton Dorney, near Windsor, England, at the 2012 Summer Olympics, Monday, July 30, 2012. (AP Photo/Natacha Pisarenko)

  • Eton Dorney

    A boy attaches a British flag to a barrier at the rowing venue in Eton Dorney, near Windsor, England, at the 2012 Summer Olympics, Monday, July 30, 2012. (AP Photo/Natacha Pisarenko)

  • Eton Dorney

    Children play on the Olympic rings at the rowing venue in Eton Dorney, near Windsor, England, at the 2012 Summer Olympics, Monday, July 30, 2012. (AP Photo/Natacha Pisarenko)

  • Eton Dorney

    Coaches and others ride bicycles next to boats competing in the rowing competition in Eton Dorney, near Windsor, England, at the 2012 Summer Olympics, Monday, July 30, 2012. (AP Photo/Natacha Pisarenko)

  • Xiaojuan Luo

    China's Xiaojuan Luo faces Tunisia's Sarra Besbes during a women's individual epee fencing round of 32 at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Andrew Medichini)

  • London Olympics

    Motorists head into central London on the first weekday of full competition of the 2012 Summer Olympics, Monday, July 30, 2012. (AP Photo/Christophe Ena)

  • Hedvig Karakas

    Hedvig Karakas of Hungary helps up Rafaela Silva of Brazil, left, off the mat after their match in the women's 57-kg judo competition at the 2012 Summer Olympics, Monday, July 30, 2012, in London. Silva lost the match by disqualification. (AP Photo/Paul Sancya)

  • Men's Rowing

    Men's teams, from top to bottom, from the Netherlands, Great Britain, Australia, Poland and Canada compete in a men's rowing eight repechage in Eton Dorney, near Windsor, England, at the 2012 Summer Olympics, Monday, July 30, 2012. (AP Photo/Natacha Pisarenko)

  • Michael Maze

    Michael Maze of Denmark serves during his men's table tennis match against Kalinikos Kreanga of Greece at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Sergei Grits)

  • Martins Reader

    Martins Reader of Canada reacts during a beach volleyball match against Norway at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Dave Martin)

  • Han Song-yi, Bojana Zivkovic

    South Korea's Han Song-yi (12) spikes the ball past a line of Serbia defenders, from left, Ivana Djerisilo (3), Milena Rasic (16), and Bojana Zivkovic (4) during a women's volleyball preliminary match at the 2012 Summer Olympics Monday, July 30, 2012, in London. (AP Photo/Chris O'Meara)

  • Acosta Bermoy, An Kae Um

    Silver medalist Acosta Bermoy, of Cuba, from left, gold medalist An Kum Ae, of North Korea and bronze medalists Priscilla Gneto, of France and Rosalba Forciniti, of Italy, share the podium after the women's 52-kg judo competition at the 2012 Summer Olympics, Sunday, July 29, 2012, in London. (AP Photo/Paul Sancya)

  • Freedom Chiya

    Freedom Chiya from South Africa fails to reach a ball during the Beach Volleyball match against Latvia at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Petr David Josek)

  • Nadine Zumkehr

    Nadine Zumkehr of Switzerland digs out a ball during a beach volleyball match against China at the 2012 Summer Olympics, Monday, July 30, 2012, in London. (AP Photo/Dave Martin)