In all three instances, the Spurs had the ball and an opportunity for the final shot of the quarter.

The Celtics, though, ended up with the only end-of-quarter score.

A turnover with 3.3 seconds left in the first quarter was one of the Spurs' most glaring mistakes.

Ahead 22-14, the Spurs got a defensive stop and a rebound by Drew Gooden with 8.9 seconds remaining. As Roger Mason dribbled into the frontcourt near the Spurs' bench, Boston's Rajon Rondo, came from behind and knocked away the ball and recovered it.

Rondo fired a pass down court to a streaking Ray Allen, who dunked it, just ahead of the end-of-quarter buzzer.

Numerous fans were yelling at Mason, trying to warn him of Rondo's approach. So were some of his teammates.

"If they were," Mason said, "I didn't hear them. I figured (Rondo) was out of the play and might go to another guy. I should have looked behind. He came and snuck it on me."

Mason had a chance to atone for the error at the end of the second period when Tony Parker drove down the lane and kicked a pass to him in the right corner.

Unguarded, the Spurs' leader in 3-pointers saw his shot go around the rim, and out.

"I love those types of passes," Mason said. "I don't get too many open looks, especially now. When I do, I have to take advantage of it."

Parker made a similar play at the end of the third quarter, driving into the lane, then whipping a pass along the baseline to Michael Finley, also unguarded in the right corner.

Finley's 3-pointer went in and out, just like Mason's had.

"It was something Tony just created, a great pass," Finley said. "I just missed the shot."

The final 1.1 seconds of the game may have been the most excruciating for the Spurs.

Finley's 3-pointer with 1.1 seconds left got the Spurs within a point at 78-77.

The situation called for a foul quick enough to give the Spurs time for a miracle 3-pointer. Unfortunately, the Spurs had committed only three fouls in the period, so the Celtics weren't in a penalty situation.

When Finley fouled Paul Pierce the instant he caught Rondo's in-bounds pass, four-tenths of a second came off the game clock, but the ball went back to the Celtics for another in-bounds play, this time with seven-tenths of a second left.

Rondo passed the ball, hard, off George Hill's foot, taking another four-tenths off the clock, effectively ending the Spurs' hopes.

"It's a tough loss, and we're in a tight, tight situation right now," Mason said. "Sunday (against the Houston Rockets) is going to be big for us."