BOSTON -- Flustered through the first three quarters, Jimmy Butler produced a breakout final period that was enough to carry the Chicago Bulls past the top-seeded Boston Celtics in the opener of a first-round Eastern Conference playoff series.
Butler scored 15 of his 30 points in the fourth quarter, including five during an 8-0 run midway through the period that put Chicago in control, and the Bulls held on to beat the Celtics 106-102 Sunday night.
"We were so locked in all week," said Butler, who also pulled down nine rebounds as the Bulls capitalized on their size advantage and controlled the inside. "We knew their stuff just like they knew ours, but we executed extremely well. We haven't done that all season, but this is the right time to do it. Everybody stepped up and did what was asked of them."
Chicago prevailed on an emotional night in Boston, as Celtics point guard Isaiah Thomas played the day after his younger sister, Chyna, was killed in a car crash. Thomas played through tears with "RIP Lil Sis" written in tribute on his shoes. He paced Boston with 33 points.
"He was incredible. He's an amazing player and an amazing person," Boston coach Brad Stevens said. "The days won't get easier for him, but he somehow plays like that."
Thomas led a last-gasp effort for the Celtics, hitting a layup with 7.5 seconds left to cut Chicago's lead to 104-102, but Butler dribbled off a few seconds and sealed it with a pair of free throws with 3.3 seconds to go.
Butler scored 23 points in the second half and finished with nine rebounds as the Bulls dominated the boards, ending up with a 53-36 advantage. The Bulls controlled inside throughout the game and forced the Celtics into shooting from the outside, where the shots stopped falling in the fourth quarter.
"It's something we've done a pretty solid job of all season long," Bulls coach Fred Hoiberg said. "The big thing is crashing the glass, but you can't jeopardize your transition defense because these guys will make you pay if they get behind you."
Bobby Portis scored 19 points off the bench, and Robin Lopez had 14 points and pulled down 11 rebounds for Chicago. Rajon Rondo added 12 points and Dwyane Wade scored 11 in his first playoff game for the Bulls.
"We don't have home-court advantage, so we had to get one here if we want to win this series," Wade said. "I think we did everything we wanted tonight."
Game 2 is Tuesday night in Boston.
It was unclear Sunday whether Thomas would play Tuesday or if he would return to Washington state to be with his family. Stevens said Thomas has the Celtics' support in whatever he decides.
"Whatever he needs to do, he needs to do, and we'll help in any way," Stevens said.
The Celtics could not overcome Chicago's size advantage inside and in the end, even Thomas wasn't enough to carry the Celtics down the stretch.
"I know it's tough for him," Bradley said. "It says a lot about him. He's a true competitor and tonight he was playing for his sister and he was playing for his family. We appreciate that as teammates. We've just got to continue to fight for him."
For a while, it was shaping up to be an emotional triumph for the grieving Thomas, who drew a foul by Rondo on a 3-point attempt and made all three foul shots to put Boston up 88-87 with 5:33 left to play. But Boston wasn't back on top for long.
Butler hit a jumper, the Bulls forced the Celtics into a shot-clock violation, and Chicago got a 3-pointer at the other end from Jerian Grant. Boston missed another outside shot and the Bulls capitalized again, with Butler drawing a foul on a 3-point try and making all three from the line with four minutes remaining.
The 95-87 lead was the largest of the game for either team and was just enough for Chicago to hang on and take the opener.
NOTES: The Celtics held a moment of silence in memory of Chyna Thomas before the national anthem. ... Celtics G Isaiah Thomas was the last player introduced in the starting lineups and received a thunderous welcome from the Boston fans. ... Former Boston G Rajon Rondo also received a loud greeting, only it was boos from fans who remembered his tumultuous years with the Celtics from 2006-14. ... The Celtics and Bulls are meeting for the fifth time in the playoffs -- all five series coming in the opening round. Boston won the previous four playoff series against Chicago, the most recent in 2009.