San Antonio forced Oklahoma City to make adjustments after blowout wins in Games 1 and 2.
Now, it's the Spurs who must adjust against a rejuvenated team.
Serge Ibaka scored 15 points in a dramatic return from what was thought to be a season-ending left calf strain, helping the Thunder beat the Spurs 106-97 on Sunday night in Game 3 of the Western Conference finals.
The Thunder also added Reggie Jackson to their starting lineup, and he scored 15 points. Oklahoma City led by 20 with 3:17 to play before clearing its bench.
The Spurs said Ibaka was the main difference after their lead was cut to 2-1.
"He played great," forward Tim Duncan said. "I think overall, their team played better. Obviously, at home, they used their energy, his return and all of that and they put us on our heels."
San Antonio now has much to fix before Game 4 on Tuesday in Oklahoma City.
"We were pretty bad," Spurs guard Manu Ginobili said. "The amount of mistakes we made in the first half were too many for a conference finals. We didn't bring concentration and aggressiveness today and they made us pay. We know that to beat them, especially here, we have to bring our 'A' game."
Ibaka started after missing the first two games of the series. The Thunder originally said he would miss the rest of the playoffs, but changed course Friday. He made 6 of 7 shots and had seven rebounds and four blocks.
Russell Westbrook had 26 points, eight rebounds and seven assists, and Kevin Durant added 25 points and 10 rebounds.
Ginobili scored 23 points and Duncan added 16 points and eight rebounds for the Spurs.
The Thunder outrebounded the Spurs 52-36 after losing the battle of the boards in the first two games. San Antonio, which shot at least 50 percent in the first two games, shot just 40 percent on Sunday night.
San Antonio won the first two games by a combined 52 points, but things were different from the start with Ibaka's return. The crowd roared when Ibaka's name was announced during pregame introductions, and it got even louder when he started playing. He had eight points, three rebounds and two blocks in just over six minutes of play in the first quarter.
Twice in the final minute of the first half, Ginobili hit 3-pointers, and both times, Westbrook answered with a 3-pointer. The last one, with 0.6 seconds left, gave the Thunder a 57-53 lead. Oklahoma City shot 56 percent in the first half, but turned the ball over 12 times. Ginobili had 20 points and made 5 of 7 3-pointers before the break to keep the Spurs close.
Oklahoma City extended its lead to 83-76 at the end of the third quarter. A runner by Durant, then a 3-pointer by Caron Butler pushed the Thunder lead to 90-76 with just over 10 minutes to play.
"I thought that our defense was pretty poor," San Antonio coach Gregg Popovich said. "Our first half was the poorest defense we've played in a really long time."
Notes: Thunder C Kendrick Perkins picked up his third foul eight minutes into the game. He played just 13 minutes and finished with four points and three rebounds. Backup center Steven Adams, a rookie, had seven points and nine rebounds. ... Thunder G Derek Fisher took a hit and was bleeding from the top of his head in the first quarter. He got six stitches. ... The Thunder shot 63 percent from the field in the first quarter but trailed 29-28 at the end of the period. ... Westbrook was issued a technical foul in the first quarter. ... Ginobili scored just three points in the second half.
Follow Cliff Brunt on Twitter: www.twitter.com/CliffBruntAP.