Kawhi Leonard and Danny Green each had 14 points, Boris Diaw added 13 and Tony Parker scored 12 for the Spurs, who are a win away from returning to the NBA Finals after losing in seven games to Miami last year.
Kevin Durant scored 25 points, but Russell Westbrook had only 21 points and seven assists after finishing with 40 points and 10 assists in Game 4.
Game 6 is Saturday in Oklahoma City.
The Jekyll and Hyde series continued between the past two Western Conference champions, as the road team has been thumped in every game of the best-of-seven series.
After losing twice in Oklahoma City by an average of 11 points, San Antonio upped its winning margin in San Antonio to 26.7 points.
“We played so much harder, sharper, smarter, everything we talked about,” Ginobili said. “It was a fun-to-play and fun-to-watch game. So when we play like this it’s a completely different story.”
San Antonio outscored Oklahoma City by 10 points in both the second and third quarters, allowing both teams to sit their starters for much of the fourth.
Serge Ibaka, who dominated the interior in Oklahoma City, was held to six points and two rebounds.
“We have to regroup and come back better in a few days,” Thunder coach Scott Brooks said.
The Spurs started Matt Bonner in place of Tiago Splitter to draw Ibaka out of the paint and it worked early. It also helped defensively, as Ibaka attacked Bonner but missed his first five shots on a series of running hooks. Duncan was also able to help defensively, rolling over to block a layup attempt by Ibaka.
San Antonio’s crowd was raucous from the start, booing Westbrook heavily during pregame introductions and erupting joyously when Green scored the team’s first points on a 3-pointer 1½ minutes into the game.
Oklahoma City withstood the early barrage, going on an 11-2 run for its largest lead of the game.
San Antonio kept Westbrook out of the paint early, but that only opened up the lanes for Jackson, who made his first five shots. He had four straight layups and then drained a 3-pointer with Parker closely defending.
Three-point shooting got San Antonio back into the game, as Patty Mills and Green closed the first with consecutive 3s to tie the game at 32-all.
Diaw’s 3 gave San Antonio a 42-37 lead with 6:12 left in the first half and resulted in an Oklahoma City timeout.
Ginobili’s 3 gave a 65-52 lead with 6.9 seconds left in the first half.
Ginobili’s third 3 gave San Antonio an 87-70 lead with 3 minutes remaining in the third.
NOTES: San Antonio used its 31st different starting lineup this season, with Bonner making his first start. He averaged 11.3 minutes in 61 regular-season games but his playing time has been curtailed to 4.8 minutes while appearing in all 16 postseason games. Diaw started in Bonner’s place in the second half. . Durant was sent back to the sideline after attempting to substitute with 10:29 remaining in the second quarter. A timekeeper told official Tony Brothers that Durant was not at the table in time to enter prior to an inbounds. “I was there,” Durant said. “That’s (wrong). You know that.” Durant was able to enter about 10 seconds later, however. . Ibaka wore a heating pad on his injured calf when he was not in the game.