Tim Duncan had 10 points and 16 rebounds, and forced Paul Pierce into a tough shot that was off the mark as the buzzer sounded, and San Antonio held off Boston, 87-86, in a battle of division leaders.
Matt Bonner had 10 points and 10 boards, and hit a big jumper in the final minute for the Southwest Division-leading Spurs, who won their ninth straight contest. Danny Green ended with 14 points and Gary Neal had 13, as San Antonio survived a nine-point third quarter and broke Boston's eight-game home winning streak.
Avery Bradley had 19 points to pace the Celtics, who remained 1 1/2 games ahead of Philadelphia in the Atlantic Division. Pierce tallied 15 points and 10 boards. Rajon Rondo chipped in 17 points and 11 assists, and Kevin Garnett scored 16, but despite rallying from a 17-point deficit, Boston's five-game winning streak came to an end.
Ray Allen, who missed the previous six games because of an ankle injury, started, but had just five points and seven rebounds for the Celtics.
Bonner's jumper from the left side came off a desperate feed from Manu Ginobili just as the shot clock was about to expire, and it expanded San Antonio's lead to 87-83 with 46.5 seconds left.
Allen then nailed a three from the right corner with 39.8 seconds to go, and the Celtics got a chance for the win after Green's three-ball from the left corner went in and out.
After a couple of timeouts, Pierce got the ball on the right side, dribbled to near the foul line, but his off-balance, fadeaway shot clanked off the right side of the rim.
The Spurs scored 24 of their 27 first-quarter points in the paint and led by seven after 12 minutes. The visitors then went 13-of-20 from the field in the second, led by Neal's 10 points. They scored 12 in a row, capped by Neal's jumper, for a 48-36 lead with 6:45 left in the half.
Boston was within 59-48 at the break and then clamped down defensively by holding the Spurs to 4-of-20 shooting in the third. Rondo's floater in the final minute fell through the basket, pulling the hosts within 68-64 going to the fourth.
Bradley's reverse layup, off a no-look pass from Pierce, finally put Boston back on top, 81-79, with 3:45 remaining.
The Spurs later scored six in a row to move to the four-point lead that set up the dramatic finish. Neal hit a big three-pointer in that run.
Rondo has 14 straight games with at least 10 assists. That's the longest streak for any player in the NBA since Steve Nash had 10 or more assists in 14 straight games in March and April of 2005...This was Boston's first home loss since Feb. 15 against Detroit...San Antonio has won 12 of its last 14 at Boston.