By John Nestor
NORTON, Massachusetts (Reuters) - British world number one Luke Donald signaled an ominous warning to his FedExCup playoff rivals by firing a five-under-par 66 in Friday's opening round of the Deutsche Bank Championship.
The Englishman mixed six birdies with a lone bogey to lurk just one stroke off the pace set by American Troy Matteson at the TPC Boston.
"It was a good round," Donald told reporters. "I feel like I've been hitting the ball pretty well the last few days. I did miss a couple (of putts) coming in but I made a good few out there and was very happy with the score."
Entering this week's event, the second of the PGA Tour's four lucrative playoff events, Donald occupies fifth spot in the overall standings and trails FedExCup leader Dustin Johnson by 1,583 points.
The long-hitting Johnson also made a good start on Friday and was among a large group including PGA Championship winner Keegan Bradley, former Masters champion Zach Johnson and Rickie Fowler after carding a three-under 68.
Matteson, a double winner on the PGA Tour, opened his round with a bogey at the 10th but rebounded with seven birdies the rest of the way to take control at the top.
He began this week a precarious 97th in the FedExCup standings and well aware he needs to sparkle at the TPC Boston if he is to advance.
The leading 70 players after the Deutsche Bank Championship move on to the BMW Championship at Cog Hill before the top 30 qualify for the Tour Championship finale at East Lake.
PLAYOFF PRESSURE
"Obviously where I'm at, if I don't play well (here) I'm not going to play next week," Matteson said.
Donald got off to a fast start with a birdie at the first but dropped a shot at the second before immediately responding with consecutive birdies.
Further birdies at the seventh, 10th and 11th put him at five under and seemingly on track to claim the outright lead but he parred his way home to stay one shot off the pace.
Masters champion Charl Schwartzel of South Africa, 2009 PGA champion Yang Yong-eun of South Korea and American Jerry Kelly ended the round level with Donald after carding matching 66s.
Four-times major winner Phil Mickelson returned a 70 after putting a belly putter in tournament play for the first time. Notably Mickelson did not three-putt once during his round.
The American world number nine hit 10-of-14 fairways on Friday and was happy with his form on the greens.
"I got off to a great start with it and I thought it went well," left-hander Mickelson said after totaling 29 putts in the opening round.
"I feel that I'm probably putting better with that putter than I would be with the short putter, so I'll end up using it for the rest of the tournament I would anticipate."
(Editing by Mark Lamport-Stokes)