HOUSTON -- Tim Duncan blocked a driving layup attempt by James Harden at the rim in the waning seconds, enabling the San Antonio Spurs to hang on for a 104-103 victory over the Houston Rockets on Friday night at the Toyota Center.

Harden, who missed 14 of 19 shots from the field, nailed a 3-pointer with 28.4 seconds left to cut the Houston deficit to one point and then harassed Spurs guard Manu Ginobili into a turnover on the defensive end, giving the Rockets possession with 6.1 seconds left.

Duncan responded with his third block of the night to go with 29 points and 10 rebounds.

The Spurs passed Houston in the standings and claimed the season series 3-1 in the event of a tie atop the Southwest Division. The Rockets fell to sixth in the Western Conference.

Rockets forward Trevor Ariza scored 19 points on 7-of-8 shooting from the field and Harden added 16 points and 10 assists. Rockets center Dwight Howard also chipped in a double-double of 12 points and 14 boards.

The Spurs utilized the strategy of intentionally fouling Rockets forward Josh Smith, who missed 14 of 26 free throws en route to a team-high 20 points. Forward Kawhi Leonard added 18 points, nine rebounds and four steals for the Spurs, who won their 10th consecutive game.

Once the Spurs responded to the Rockets' opening 12-0 salvo, Houston spent the following two-plus quarters fighting doggedly to keep its lead.

San Antonio had its reserves to that for the initial surge back into contention, with forward Boris Diaw, Ginobili and center Jeff Ayres leading an 11-3 spurt that cut a 13-point deficit to 28-23. From there, the Rockets kept responding to San Antonio surges, mostly with timely 3-pointers that kept the hard-charging Spurs at bay.

After the Spurs clawed to 43-32, Rockets forward Josh Smith tossed in a hook shot and added a breakaway dunk for a five-point lead. San Antonio closed to 42-40 on back-to-back Duncan baskets only for Harden to answer with a pull-up 3-pointer with 2:23 left in the half.

Rockets guard Jason Terry drilled a 3 with the Spurs trailing by one with 19.1 seconds left in the second quarter, and with 4:00 left in the third quarter, Ariza did the same to snap a 64-64 tie. Ariza added another trey with 2:59 left in that quarter to put Houston ahead 71-68, but momentum was already slipping away from the Rockets by that point.

With 4:24 remaining in the third quarter, the Spurs began to intentionally foul Smith, a 49.5 percent shooter from the line this season. Smith missed 7 of 10 free throws down the stretch in the quarter and the Spurs again caught fire behind their bench. San Antonio capped the third with eight consecutive points, including guard Patty Mills' 3-pointer with 39.1 seconds left, giving the Spurs their first lead of the game at 77-74.

NOTES: Spurs C Tiago Splitter missed his fourth consecutive game with right calf tightness. ... With the regular season coming to a close and the Rockets guaranteed entry into the playoffs, Rockets coach Kevin McHale was asked if he has begun considering his postseason rotation with the caveat that those rotations are usually just three or four deep. "We've had our rotation shortened already," McHale quipped, referencing the season-ending injuries suffered by G Patrick Beverley (left wrist) and F/C Donatas Motiejunas (back). ... The Rockets continue to work through the minutes restriction placed on C Dwight Howard, who entering Friday had yet to play 23 minutes in any of the six games since his return from right knee surgery. "It's been hard on him," Rockets coach Kevin McHale said. "It's been hard on everybody."