After Rajon Rondo  and Paul Pierce  each missed potential game-winnters to end regulation and the first overtime, they combined for 10-of-12 points in the second OT as the Celtics  outlasted the Mavericks, 117-115. Courtney Lee  scored the other two, a pair of free throws that kept an O.J. Mayo 3-pointer at the buzzer from forcing a third overtime.
Pierce finished with a season-high 34 points, Rondo missed his second triple-double in three games by a single rebound (16 points, 15 assists, 9 rebounds) and four other Celtics reached double figures: Kevin Garnett  (16 points), Jeff Green  (15 points), Jason Terry  (10 points) and Chris Wilcox  (10 points).
In a wild final two minutes of regulation, Derek Fisher‘s 3-pointer gave the Mavericks their first lead, 95-94 with 1:47 to play in the fourth quarter. A Pierce jumper briefly gave the Celtics the lead back, but O.J. Mayo made 1-of-2 free throws to force a tie. That resulted in a seven-second span in which Rondo poked the ball loose from Mayo with 6.9 seconds left and got his shot blocked by Fisher as time expired on the other end.
Likewise, in the first overtime, Pierce and Garnett each drilled go-ahead jump shots in the final minute, but Shawn Marion  (16 points, 11 rebounds) and Mayo (team-high 21 points) answered on both occasions. And the unimaginative Pierce elbow jumper failed as the clock ran out on OT No. 1.
A Pierce triple to begin the second overtime gave the Celtics the lead for good, as they held off every run the Mavericks had left in them, including a Vince Carter  trey that brought them within one in the final minute.
WHAT WENT RIGHT
Early birds: Celtics coach Doc Rivers  didn’t hold practices on Sunday or Monday and held a 90-minute session on Tuesday. Garnett, Pierce and Rondo needed the rest. The trio totaled 15 points (7-10 FG) and seven assists in the first quarter, when their teammates combined for 12 points (3-12 FG) and zero assists. The C’s All-Star triumvirate helped stake them to a 27-25 lead after one that they didn’t relinquish until the fourth quarter.
Mean Jeff Green: His 5-of-15 shooting be damned, Green played like the guy the Celtics need off the bench. He collected seven points — including a corner trey that raised his season average from that spot to 53.8 percent — to go along with four rebounds in the first half. Green only grabbed that many boards in four of his first 16 games. He’s now reached that plateau in 4-of-5 games in December, when he’s averaging 14.4 points and 4.6 rebounds.
Big help: Speaking of active reserves, Wilcox held the fort as Garnett sat the final 7:21 of the first quarter, totaling four points (a layup and a pair of free throws after a missed layup) and three offensive boards in that span. Entering the game, 41 of his 48 shots had come from the restricted area, where he was shooting 75.6 percent.
Truth matters: It wasn’t always pretty, but Pierce finished with a season-high 34 points (he’s had 27 on three separate occasions) on 11-of-25 shooting, including 12 points in the two overtime periods. His 3-pointer to start the second overtime put the tired Mavericks on their heels, and his 5-of-6 free throws in the final 19 seconds kept Dallas at bay.
WHAT WENT WRONG
No D on Dallas: After a few days of discussion about how their defense has improved over the past handful of games, the Celtics allowed the Mavericks to shoot 70 percent for the first 6:32. Chris Kaman , Marion and Mayo combined for 14 points on 7-of-12 shooting to help offset the torrid start from Garnett, Pierce and Rondo.
Cold seconds: Somehow, the Celtics shot just 36.8 percent (7-19 FG) in the second quarter and actually increased their lead to 48-43 at the half — thanks to improved defense (held the Mavericks to 40%) and Pierce’s 4-of-5 shooting (11 points) in the frame. Everybody else on the C’s shot a combined 3-of-14 (10 points).
Paint points: It’s been a problem all season. The Celtics entered allowing 42 points in the paint per game, which ranks among the bottom third in the NBA. Wednesday night didn’t help matters, as the Mavericks scored 60 points in the key, including 16 in an ugly fourth quarter that saw their one-time 14-point lead evaporate. Even Fisher waltzed through the lane for a layup that forced a timeout from an irate Rivers.
Hold the Mayo: After Tuesday’s practice, the Celtics expressed concern about cooling Mayo’s hot scoring . Regardless, he scored 24 points on 10-of-19 shooting, including a beautiful driving layup that tied the game at 105-105 with 11 seconds left in the first overtime.