Jimmy Butler had 30 points and nine rebounds as the Chicago Bulls outlasted Boston 106-102 in Game 1 on an emotional day for grieving Celtics star Isaiah Thomas.
Playing a day after 22-year-old sister Chyna Thomas was killed in a car accident in their home state of Washington, Thomas led the top-seeded Celtics with 33 points.
Celtics fans rallied behind Thomas, showering him with a deafening cheer when he was introduced.
Butler scored 23 points in the second half. Bobby Portis finished with 19 points and nine rebounds for the Bulls.
Al Horford had 19 points, eight rebounds and seven assists for Boston.
Game 2 in the first-round series is Wednesday in Boston.