Well-taken strikes from Jordi Alba, Cristian Tello and Lionel Messi made it 3-0 to Tito Vilanova's side inside 20 minutes, before Pizzi reduced the deficit with a penalty. Alex Bergantinos then beat Valdes with a half volley from distance before Messi made it 4-2 with a low finish from 15 yards shortly before the break.
Pizzi grabbed his second with a fine free kick shortly after halftime before Barcelona's Javier Mascherano was sent off for a second yellow card after an altercation with Riki. Messi completed his hat trick with an explosive run and finish in the 77th minute, but there was still time for more drama as Alba sent a volley past his own goalkeeper Victor Valdes to make it 5-4.
The visitors gave a firm signal of their intentions for this match by taking the lead after just three minutes through Jordi Alba. The Spain international took a pass from Cesc Fabregas in his stride brilliantly before stroking a shot past Dani Aranzubia to make it 1-0 to Barcelona.
Within five minutes they had increased their lead to two, after a driving run and clipped pass from Lionel Messi found Cristian Tello on the right. The youngster immediately set off for goal, turning the Deportivo left back Ayoze inside-out on the edge of the box before hammering a low shot between the legs of Aranzubia.
Not to be outdone by the goalscoring exploits of his teammates, Lionel Messi soon added his name to the scoresheet, smashing in Barcelona's third with his left foot from 18 yards after a delightful backheel from Fabregas had pulled Deportivo's two center backs Carlos Marchena and Ze Castro out of position and cleared the way to goal for his Argentine teammate.
Despite their imperious attacking play Barcelona offered Deportivo a chance to get back in to the match when Javier Mascherano caught Pizzi with a sliding challenge as he burst into the penalty area. The referee awarded a penalty despite the Barcelona players suggesting the foul was outside the box, and Pizzi wasted no time in stepping up to take the spot kick he had won and confidently dispatching it past Victor Valdes to reduce the deficit to 3-1.
Deportivo struck again shortly after through Alex Bergantinos, the midfielder making it 3-2 in the 37th minute with a well-struck half volley from the edge of the box that ricocheted off Valdes and into the back of the net.
The flurry of first-half goals did not stop there though, as Messi scored the sixth goal of the half, and his second of the evening, running on to a fine outside-of-the-boot pass from Fabregas before firing a low shot into the bottom left-hand corner of Aranzubia's goal.
Any who thought the second half would not live up to the first were given a jolt in the 47th minute as Pizzi curled an inch-perfect free kick into the top right corner from 25 yards to cut Barcelona's lead to just one and ensure the second 45 minutes continued in a similar vein to the first.
Minutes after Pizzi had made it 4-3, Barcelona was reduced to ten men following the sending off of Javier Mascherano for a second bookable offense. Referee Jose Paradas deemed the Argentine to have caught Riki with a flailing arm after the striker dribbled towards him but replays showed that he got the ball and made little contact with the Deportivo player.
Messi then came within millimeters of completing his hat trick from a set piece as his vicious free kick from 30 yards came cannoning back off Aranzubia's left-hand post and away to safety.
After hitting the crossbar with a wicked free kick, Messi did eventually notch his third of the night in the 77th minute. After dispossessing Ze Castro 45 yards from goal, the Argentine powered towards the Deportivo goal before unleashing an unstoppable shot into the bottom right corner with his left foot.
A moment of madness from Alba supplied Deportivo with a lifeline, as he volleyed the ball into his own net under pressure from Riki inside the Barcelona penalty area to make the score 5-4.
Deportivo committed men forward late on as it went in search of an equalizer but Barcelona's makeshift defense managed to withstand the pressure and hold out for all three points to retain its place atop of La Liga.
Follow @GoalUSA on Twitter.