Sidney Moncrief, who started with 13 points the first quarter, scored six in the stretch to complete a 27-point performance and lead Milwaukee to victory in Boston.
The game marked the first time in regular season that Dave Cowens faced his ex-Boston teammates. Cowens, who spent the last two seasons in retirement, had 10 points.
Milwaukee ended a two-year winless period at Boston Garden. The Bucks had been 0-6 there since Nov. 8, 1980.
After Boston took its 89-82 lead, "our defense really started to anticipate more," Moncrief said. "We became a little more patient on offense. We only took good shots, and they hit a cold spell."
Milwaukee went ahead, 92-91, with 6:36 left, and the lead changed three times before Moncrief sank a jumper to give the Bucks a lead for good with 2:33 remaining.
"They could have blown us out," Moncrief said. "But, we stopped their break and got them into a half-court game."
Two free throws by Cowens stretched Milwaukee's lead to 101-97, but a jumper by Robert Parish cut it to 101-99 with 44 seconds to go.
Then Moncrief helped seal the victory with two free throws 17 seconds later. McHale had a field goal with 10 seconds remaining, but Junior Bridgeman made two foul shots three seconds later to clinch Milwaukee's fifth victory in seven games.