An 18-2 run over the final 5:30 in the opening period gave the Thunder a 17-point lead that they would eventually stretch to a 43-20 advantage early in the second quarter.
The Spurs cut that deficit to seven points at halftime before taking an 81-78 lead when Manu Ginobili hit a three-pointer 23 seconds into the fourth quarter.
Carmelo Anthony appeared to tie the game at 102 on a three-point basket with 5.6 seconds left on the clock, but a review showed his left toe was touching the line, which kept San Antonio ahead 102-101.
After Pau Gasol was fouled on the inbound pass, he hit two free throws to extend the Spurs' lead back to three points. The Thunder's last shot came up short when Russell Westbrook's feet got tangled with Ginobili.
LaMarcus Aldridge and Danny Green led the way for San Antonio with a combined 43 points on 14-of-29 shooting and 15 rebounds.
San Antonio's win moved its record to a solid 10-6, despite not having Kawhi Leonard suit up yet this season because of a quad injury.
On the other side of the spectrum, the Thunder (7-8) have been a disappointment in the early going, especially on the offensive side of the ball. They entered Friday ranked 17th in offensive efficiency and 22nd with 103.1 points per game.
Westbrook's 41.6 shooting percentage is the second-worst of his career, trailing only his rookie season in 2008-09 (39.8 percent). Anthony hasn't been much better with the worst field goal success rate (41.8) during his 15-year NBA career.
When Oklahoma City was building its big lead at the end of the first quarter, Westbrook was still finding ways to impact the game with his other unique talents:
When the Thunder needed their top playmakers to seize the moment, though, they did not. Anthony tied his second-best shooting game by percentage (52.9) of the season, but his extra step on that play in the final seconds cost the team an opportunity to force overtime.
Westbrook and Paul George were a mess shooting the ball. The duo made 10 of its 38 attempts.
One month together for this new-look Thunder, Westbrook has said he's doing what he can to make Anthony and George feel comfortable playing their style of basketball.
"That's a part of my job to make sure those guys are [comfortable]," Westbrook told ESPN.com's Royce Young. "Those guys are great players, and my job is to make sure they're comfortable, and in their spots, and comfortable with the things that best benefits their game."
But as he was watching Friday's game, Brett Dawson of the Oklahoman offered one observation about Westbrook this season:
The Spurs used Westbrook's shooting issues to their advantage as they made their comeback. They also had just one turnover in the third quarter, a drastic change from where they were at in the first half:
One Spurs player whose performance directly echoed what the entire team did was Ginobili, as noted by SB Nation's Pounding the Rock:
Ginobili made two of the Spurs' first three field goals of the fourth quarter, both three-pointers, and had eight points off the bench for head coach Gregg Popovich.
The Thunder did keep fighting after their big lead evaporated. Westbrook converted a three-point play with six minutes remaining to tie the score at 91. His layup before getting fouled was just his second made shot in 14 attempts after the first quarter.
Something was in the air for teams that jumped out to double-digit leads on Friday night, with John Schuhmann of NBA.com offering this tidbit of information:
This is part of a larger sign of trouble for the Thunder, who continue to have issues finishing in close games:
It's still early in the season for Oklahoma City, but with little improvement in some fundamental areas still showing up, head coach Billy Donovan has a lot of work ahead of him.
Meanwhile, the Spurs keep chugging along, doing more than just treading water as they continue to await the return of Leonard.
Stats via Basketball-Reference.com unless otherwise noted.