BOSTON (AP) — Tim Duncan scored 23 of his 25 points in the second half, powering the injury-depleted San Antonio Spurs to a 104-92 win over the Boston Celtics on Wednesday night.

Marco Belinelli added 16 points, 11 rebounds and eight assists for the Spurs, who were without guards Tony Parker and Manu Ginobili and forward Tiago Splitter — all sidelined with injuries.

Boris Diaw added 18 points and Duncan grabbed nine rebounds to lead the Spurs to their fifth win in seven games.

Rajon Rondo led Boston with 16 points and Kris Humphries and rookie Kelly Olynyk had 15 apiece. The Celtics fell to 4-18 against Western Conference teams.

Boston was minus guard Avery Bradley, who was sidelined with a sprained right ankle.

After the Celtics scored the first points of the fourth quarter on Humphries’ jumper, San Antonio went on a 12-4 run. The Spurs went 6 of 8 to start the period, keyed by Green’s 3 from the left corner that made it 79-70 with just under 10 minutes to play.

After a foul-line jumper by Humphries, Duncan had consecutive baskets, the second a jumper that pushed the Spurs’ lead to 85-74 with 8:06 left.

San Antonio broke it open with a 11-0 run midway into the quarter that was capped by Belinelli’s 3-pointer with 4 minutes left.

The Spurs used a 9-2 run late in the third to take a 71-66 lead heading into the fourth. Duncan, who didn’t score his first points until a basket late in the first half, had 11 points in the quarter.

The Celtics went on a 12-0 run, bridging the end of the first quarter and the start of the second to pull to their first lead of the game, 26-25, on Phil Pressey’s 3-pointer.

San Antonio led 48-44 at halftime.

NOTES: Boston coach Brad Stevens said Bradley re-sprained the ankle that cost him five games at the end of January. Stevens said he could be out after the All-Star break. … Stevens praised the Spurs’ ability to overcome the loss of players due to injuries. “I think some of the most inspiring basketball I’ve ever watched is when they don’t have all their players,” he said. … The Spurs played their sixth game of a nine-game road trip that will carry over the break with the final three. Boston opens the post-break schedule with a four-game trip, starting against Phoenix next Wednesday. … Hall of Famer Bill Russell turned 80 Wednesday. … San Antonio beat Boston at home on Nov. 20, 104-93 in the only other meeting this season.