BOSTON -- The Oklahoma City Thunder might have thought they had Paul Pierce bottled up.
Then he broke through with 22 second-half points.
"Paul Pierce is one of the more crafty guys in this league," Oklahoma City coach Scott Brooks said after the Boston Celtics beat the Thunder 108-100 on Friday night. "You don't think he can get around you, but he gets around you. You don't think he can get the shot off, but he gets it off. He just has a knack for making the right play."
Pierce scored 22 of his 27 points after the half, and the Celtics snapped a two-game losing streak by beating the defending Western Conference champions. Kevin Garnett had 18 points and nine rebounds for the Celtics, and Rajon Rondo had 16 assists and eight rebounds.
Kevin Durant scored 29 points for Oklahoma City, which trailed by 14 before cutting the lead to three points with under 2 minutes remaining. But Durant missed a 3-pointer that could have tied it, and the Celtics pulled away.
"Oh, man, it felt good," Durant said. "It left my hand, it was online. I'd take that shot 10 out of 10 times. I shot it well. Unfortunately, it just bounced out."
Russell Westbrook had 26 points, eight assists and seven rebounds, and Serge Ibaka added 17 points and 13 rebounds for the Thunder, who lost for just the second time in their last 10 games.
"It's great to beat Oklahoma," Celtics coach Doc Rivers said. "They were in the finals last year, and they're the team to beat, I guess, in the West. But it was more how we played. We played with great force tonight."
The Celtics had struggled to a .500 record so far this season, with two of their six victories against winless Washington and another against Toronto, which is in last place in the Atlantic Division. It was just their second win against a team that had a winning record heading into Friday night.
"It's big for us," Pierce said. "This is a gut-check type of a win, a 'look yourself in the mirror' type of game. ... I know we are capable of playing against quality opponents."
Boston led 84-70 on Pierce's 3-pointer with just under 10 minutes left, but the Thunder cut it to six, 93-87, thanks in part to a 3-pointer from Durant and a dunk from Ibaka. It was 101-89 when Westbrook made a pair of free throws and Durant hit a 3-pointer, then they each added a pair of free throws to cut the deficit to three points.
But Durant's 3-point attempt was a little short, then Garnett's free throws gave Boston back a cushion. Jason Terry hit a 3-pointer with 37 seconds left to clinch it.
Kendrick Perkins had five points and nine rebounds in his second game in Boston since he was traded to Oklahoma City by the team he helped win the 2008 NBA championship. Jeff Green, the only remaining player on the Celtics from that deal, scored 17 points off the bench.
Pierce matched his season-high in points, taking advantage of Durant after he picked up three fouls early in the second quarter.
"He's got a lot of tricks," said Perkins, his former teammate. "That's the reason he's been scoring the ball like he has for years. Got a lot of tricks, man. He did a great job tonight of just playing smart.
The Celtics trailed by seven points after one quarter but took a 48-45 lead into the half. They quickly expanded it to eight thanks to three straight baskets from Pierce, including a 3-pointer that made it 55-47 just 1:18 into the third quarter.
It got as high as nine points before the Thunder came within two, 66-64 with Garnett and Pierce on the bench. But Garnett came back into the game and Boston scored the next 11 points before Kevin Martin made a free throw with 2 seconds left in the third to make it 77-65.
Pierce hit a 3 to make it 84-70 with 9:52 to play, Boston's biggest lead of the game.
