Houston, TX (SportsNetwork.com) - Tim Duncan posted 29 points and 10 rebounds, but it was his last-second block on James Harden that fans will remember in the San Antonio Spurs' 104-103 win over the Houston Rockets on Friday.

San Antonio led by one when Harden forced Manu Ginobili into a turnover, giving the ball back to Houston with 6.1 seconds to play. Harden isolated on Kawhi Leonard out of a timeout and drove with his dominant left hand, but Duncan was there to meet him at the rim.

He turned aside the layup, then secured the rebound as the clock expired.

"Got to finish," Harden said. "I've just got to finish."

It went down to the wire, but the Spurs found a way to extend their league best win streak to 10 games. They are 20-3 over their past 23 games.

The win also gave San Antonio a half-game lead over the Rockets in the Southwest Division, though Memphis still leads the division with a one-game edge on San Antonio in the loss column.

Leonard had 18 points and nine rebounds, and Patty Mills made all four of his shots, including three 3-pointers, for 14 off the bench.

Harden, one of the league's top candidates for MVP, had just 16 points and 10 assists on 5-of-19 shooting.

The Spurs turned a two-point halftime deficit into an 80-75 lead through three after holding Harden without a point on 0-of-8 in the period. Mills hit two straight triples to close the quarter.

They also used a Hack-A-Smith strategy in the second half, fouling Josh Smith intentionally and force the sub-.500 percent free throw shooter to beat them. Smith was true to his average, going 12-for-26 from the line in the second half.

"I'd trade it any day rather than have James Harden with the basketball," Popovich said of the strategy.

He missed five straight at the charity stripe midway through the fourth. Leonard made a pair of jumpers around the missed free throws to extend the Spurs' lead to 98-83. Smith finally got on track with three makes from the line, and Corey Brewer got a layup to go to tie it with 4:12 to play.

Boris Diaw, Leonard and Duncan all made two free throws in the final 3:36 for the remaining Spurs points.

Smith finished with 20 points, while Dwight Howard tallied 12 points and 14 rebounds in Houston's second straight loss to San Antonio.

The Rockets led 30-23 after the first quarter 48-47 at the half.

Game Notes

The Spurs took the season series, 3-1 ... Smith had never attempted more than 16 free throws in a game ... Trevor Ariza scored 19 points for Houston ... Smith set a new NBA record for free-throw attempts in a half with 26 after the break.