Pierce scored 27 points -- his best performance of this year's Finals -- and the Celtics withstood 38 points from Kobe Bryant to beat the defending NBA champion Los Angeles Lakers 92-86 on Sunday night and take a 3-2 lead in the best-of-seven series.
Game 6 is Tuesday night in Los Angeles, and a victory then or in Game 7 in L.A. on Thursday would give the Celtics a record 18th NBA title.
The Celtics have never blown a 3-2 lead in the NBA Finals.
"It was our biggest game of the year," Pierce said. "We're in a good spot. We have two games in L.A.; now we have to get one."
Bryant was the MVP of the Finals last year, when the Lakers beat the Orlando Magic to win their 15th championship. But Pierce earned the honor at his expense in '08, when the new Big Three beat the Lakers to raise an NBA-record 17th banner to the rafters at Boston's TD Garden.
Bryant outscored Pierce this time, but the Lakers' guard got little help from his teammates. And the stretch where he was most dominant was also the time when the Celtics pulled away.
"I wasn't in a personal duel," Pierce said. "I didn't notice that we were going back-and-forth scoring at the time. He's a tough player. He makes shots."
Lakers coach Phil Jackson defended Bryant's attempts to take over the offense.
"He's the kind of guy [where] you ride the hot hand, that's for sure," Jackson said. "We were waiting for him to do that. ... He went out there and found a rhythm."
With the "Beat L.A.!" chant reverberating at the Garden, Kevin Garnett scored 18 points with 10 rebounds and Rajon Rondo had 18 points, eight assists and five rebounds to help Boston become the first team in the series to win two games in a row. If Los Angeles can't do the same at home, the Celtics will improve to 10-2 against them in the Finals, from a 4-0 sweep over the Minneapolis Lakers in 1959 through the Bird-and-Magic era of the '80s and Boston's win in '08.
But Bryant said neither the rivalry nor revenge should be motivating his teammates when they try to stave off elimination at home.
"Just man up and play. What the hell is the big deal?" he said. "If I have to say something to them, then we don't deserve to be champions. We're down 3-2: Go home, win one game, go into the next one. Simple as that."
Bryant did everything he could to send the Lakers home with the edge.
He scored 23 straight Lakers points between the 4:23 mark of the second quarter until there was 2:16 left in the third. But over that span, the Celtics expanded the lead from one point to 13.
"I just tried to keep telling them, 'It's only 2 points each time he scores. It's not 10,'" Celtics coach Doc Rivers said. "It's just like if someone else was scoring. ... I love that our guys for the most part, they understood what he was doing. But we defended everyone else. And I thought it was big."
And Pierce was having his best game of the series, too.
The Celtics' captain scored seven points in the last 3½ minutes of the second quarter and added nine more in the first 5 minutes of the third. Ray Allen, who hasn't hit a 3-pointer since making an NBA-record eight in Game 2, made a pair of baskets that gave Boston a 71-58 lead with 3:08 left in the third.
Jackson, wearing a microphone for the TV broadcast, told his players during a late timeout, "This team loses more games in the fourth quarter than any team in the league. They know how to lose games, and they're showing us that now."
The Lakers got within six points several times, but never within five until Bryant made three free throws to make it 87-82 with 90 seconds left.
The Celtics got a break from a review when replays showed Allen's 3-pointer barely nicked the rim, giving them the ball with a fresh 24 seconds and 1:05 left. Rasheed Wallace missed a 3-pointer, but the rebound wound up tied up between the 6-foot-11 Garnett and 6-foot-1 Derek Fisher.
Fisher won the jump ball, tipping the ball ahead to Ron Artest for a breakaway; Pierce fouled him to keep him from scoring an easy layup, and he missed both free throws. Bryant grabbed the rebound, but Pierce ripped it out of his arms and dribbled off to the side to call timeout.
A desperate inbound pass went to Pierce, who fed Rondo under the basket before falling out of bounds, and Rondo made an over-the-head layup to make it 89-82 with 36 seconds left.
"I was just showing off my Randy Moss and my [Tom] Brady the whole play," Pierce said. "I was Randy when I caught it; then Brady on my pass to Rondo."
Bryant missed a series of desperation 3-pointers down the stretch, and when Allen made two free throws with 19 seconds left and Garnett one of two with 8.9 to play, it was over.
"He's the best shot-maker in the game. There's probably better athletes and all that, but there's no better shot-maker than Kobe Bryant," Rivers said. "You've just got to live with it and play through it."
Pau Gasol scored 12 points with 12 rebounds and Fisher, the Game 3 star, scored all nine of his points in the first quarter as no other Laker reached double figures in scoring until Gasol hit a free throw with 2:25 left. Andrew Bynum played on his sore right knee for 31 minutes, but he scored all six of his points and his only rebound came in the first quarter.
Of the 25 finals that have been tied at 2-all, the winner of Game 5 has won 19 of them. ... Rondo was called for a technical foul in the second quarter when he pushed Artest in retaliation for a hard foul on Garnett. Artest embellished the shove, but got the call. ... Celebrities in the crowd: sprinter Usain Bolt, actress Eliza Dushku, Red Hot Chili Peppers bassist Flea and singers Glen Frey and Jimmy Buffett, Philadelphia Phillies slugger Ryan Howard and New England Patriots coach Bill Belichick.