Rondo had six rebounds and five assists in the third quarter, when the Celtics went on a 20-4 run to turn a five-point deficit into a double-digit lead. The Bucks cut it to two points in the final minute, but Kevin Garnett made four free throws in the last 15 seconds to clinch it.
Garnett scored 25 points with 10 rebounds, and Chris Wilcox came off the bench to grab 13 rebounds in 26 minutes for Boston, which returned to .500 with its second straight win.
Ersan Ilyasova had 25 points with 10 rebounds and Drew Gooden scored 23 for the Bucks.
Brandon Jennings had just six points to go with his eight assists, but he pulled up for a fast-break 3-pointer that made it 98-93 with 79 seconds to play.
Ilyasova hit a putback that cut it to 98-96 before Garnett sank a pair of free throws with 14.4 seconds left. The Celtics gave Jennings a layup but he missed it, and he also missed a 3-point attempt before Garnett grabbed the rebound and went back to the foul line for two more free throws.
Brandon Bass, making his second consecutive start because of Jermaine O’Neal’s wrist injury, scored 16 points with seven rebounds for Boston. Milwaukee led 60-55 with 8:34 left in the third quarter when the Celtics scored the next 12 points and 20 out of 24 to open an 11-point lead.
Both teams were playing for the second consecutive night following the All-Star break.
The Bucks were coming off a 119-118 victory over the Washington Wizards earned when Ilyasova tipped in Jennings’ miss with 2.2 seconds left. Boston, which took a five-game losing streak into the break, beat Cleveland on Tuesday to hold onto eighth place in the Eastern Conference.
For the second straight night, the Celtics faced their closest pursuer for the East’s final playoff berth.
Ilyasova had 10 points in the first quarter and Rondo had eight, when the teams finished tied 25-all. The Bucks took the lead with Larry Sanders’ tip-in on the first possession of the second quarter and led for the rest of the half, but Boston cut a nine-point deficit to four just before the break when Rondo drove for a layup and then Allen stole the ensuing inbounds pass to set up Keyon Dooling’s 3-pointer with 0.9 seconds left.
Notes: Garnett and Sanders exchanged words, drawing a double technical foul with 6:23 left in the second quarter. … Drew Gooden had 16 points and six assists and Jennings had seven assists at the half. … O’Neal missed his third straight game with a sprained left wrist. … Mike Dunleavy picked up a technical foul complaining after he was beaten for a rebound by Rondo down the stretch. … It was Rondo’s 16th career triple-double.