That the ball was headed to Scola with the game on the line wasn't unexpected. On this day, he had been Houston's leading scorer not named Ron Artest.

That the basket was so wide open? Against the Spurs? In crunch time of a need-to-win game in March?

Scola couldn't have been more surprised had he woken up Sunday morning in a Spurs uniform.

Taking advantage of the Spurs' late defensive lapse, Scola slipped in for a layup off a feed from Yao Ming with 11.2 seconds to go, providing the Rockets' go-ahead points in an 87-85 win at the AT&T Center.

"We had some defensive breakdowns at the end of the game," guard Roger Mason Jr. said. "We know that's where the game is won."

Or, more often for the Spurs lately, where it is lost.

It was the Spurs' third loss in four games, all three coming down to a final possession, a stretch of crunch-time anti-heroics that has evicted them from first place in the Southwest Division for the first time since Jan. 6.

Houston (47-25) takes over pole position, moving a half-game ahead in both the division and the race for the Western Conference's second seed.

The Spurs (45-24), who led 79-72 with 5:58 to play Sunday, had two chances to retake a lead in the final seconds.

With the Spurs behind 86-85, Tony Parker missed a running jumper. Scola rebounded and was fouled with 0.3 seconds left.

After missing the first free throw, Scola tried to intentionally miss the second, which by rule would have run the remaining three-tenths of a second off the clock.

Instead, Scola accidentally sunk the free throw, eliciting a groan from the Houston bench. Let the record show it was the second straight game at the AT&T Center in which a team bemoaned its foul-line fate.

Scola finished with 19 points and 17 rebounds, trailing only Artest (24 points) for the team lead.

Down to a last shot, the Spurs' Matt Bonner got an unfettered look at a 3-pointer from the top of the arc. It hit the back of the rim.

"I thought it was in," Bonner said. "Anyone who has ever shot a Basketball knows that feeling. A shot leaves your hand and you think, 'It's in, it's in.' And then it doesn't go in."

Spurs coach Gregg Popovich couldn't complain about his team's final shot. But he could and did grumble about the end-game defensive hiccups that made a Hail Mary necessary.

"We made three defensive errors down the stretch that really cost us," he said. "Just bad execution the last three possessions was the ball game."

Popovich declined to name the party responsible for Scola's go-ahead layup, but he was last seen barking at Tim Duncan.

After the game, Duncan fessed up.

"It was my fault," said Duncan, who did contribute 23 points for his first 20-point game since Feb. 17. "(Yao) popped to the top. I didn't see anybody rotating to him, so I tried to kind of half-rotate to him. I thought he was shooting the ball, so I turned to block out.

"(The pass) went right by my head."

Duncan had reason to look elsewhere. Asked afterward how many times Yao had hit Scola for such a layup, Houston coach Rick Adelman chuckled.

"Twice," he said. "That's about it."

The other had come seconds earlier, when Yao first found Scola to give the Rockets a short-lived 84-83 lead.

After Parker answered with a go-ahead layup of his own, Yao and Scola produced an encore.

"It's a huge loss, especially with the race as close as it is," Duncan said. "We came in here knowing the importance of this game. Just wish it could have bounced the other way."