Down 83-76 going into the final period, the Bucks kicked into life, scoring more than 30 points before the buzzer called time.
The hosts romped home on a 10-0 run, forcing Toronto to miss their final eight shots.
Brook Lopez scored 13 of his play-off career high 29 points during the Bucks blitz, while Giannis Antetokounmpo added 24 and Malcolm Brogdon 15.
Indeed it was Lopez’s dunk with two minutes 20 of the game left that put Milwaukee ahead for the final time.
For the Raptors Kawhi Leonard scored 31 points and Kyle Lowry added 30.