Jrue Holiday added 19 points and 10 assists for Milwaukee, which established control by darting to a 13-0 lead out of the gate.
Tyrese Haliburton contributed 24 points, 10 assists and five steals, while Jalen Smith had 19 points and 15 rebounds for Indiana.
Jaden Ivey had 17 points, 11 rebounds and five assists, Bojan Bogdanovic fired in 16 points and Isaiah Stewart added 11 points.
Evan Mobley added 16 points and Kevin Love sank five 3-pointers as part of his 15-point, 12-rebound performance.
Josh Giddey added 19 points and 12 rebounds, and Mike Muscala scored 18 off the bench for Oklahoma City.