The Celtics can finish off the Hawks in Atlanta on Tuesday. Game 6 would be in Boston on Thursday, if necessary.
Two nights after his triple-double helped turn back the Hawks in overtime in Game 3, Rajon Rondo had 20 points and 16 assists as the Celtics got some much-needed rest for their aging and injured roster.
Josh Smith returned after missing Friday's game and had 15 points and 13 rebounds for Atlanta. Al Horford, who played for the first time in almost four months, scored 12 points.
Rondo, whose triple-double Friday was the seventh of his career, may have been even better in Game 4, shooting 8 for 11 from the floor and sinking a pair of 3-pointers — tying a career high.
Perhaps the biggest boost of all for the aging and injured Boston lineup: Rondo and Brandon Bass were the only Celtics to play more than 30 minutes.
Pierce limped off the court favouring his left knee midway through the second quarter, but he returned for the start of the third. He was on the court as Boston scored 16 of the first 18 points in the second half to open an 80-37 lead with 8:13 left in the third quarter.
That was enough to earn Pierce, who played 47 minutes on Friday, some much-needed rest. Avery Bradley, who dislocated his shoulder in Game 3, played just 19 minutes Sunday and Ray Allen, who played 37 minutes Friday in his first game in more than three weeks, sat down after scoring 12 points and pulling down five rebounds in 19 minutes in Game 4.
The teams went to the locker rooms at the half with Boston holding a 63-41 lead. But during the break, the officials reviewed a jumper by Ray Allen and changed it from a 2-pointer to a 3-pointer. Rondo hit a 3-pointer to open the third quarter, giving Boston a 26-point lead, then Bass made a jumper and Pierce hit a 3 to make it 72-41.
By the time the Celtics were done with the 16-2 run to start the half, they led 80-43 and coach Doc Rivers was emptying his bench. Pierce headed for the tunnel to the locker room and pulled over a stationary bicycle to stay loose in case he was needed again.
The Hawks weren't able to get any closer than 22 points before Rondo and Allen hit back-to-back 3-pointers, then Rondo made a behind-the-back fake to clear out the lane for an easy layup as Boston closed out the third quarter with a 90-63 lead.
Atlanta did cut it to 20 points in garbage time before Keyon Dooling made a 3-pointer with just under 2 minutes to play.
Notes: Presumptive Republican presidential nominee Mitt Romney attended the game with his wife, Ann. They left their mid-court seats with about 6 minutes left and Boston leading 98-71. ... The Celtics shot 64 per cent in the first half. ... Tracy McGrady, a key contributor for Atlanta in Game 3, had just two points in 9 minutes.