CHICAGO -- Given the week Isaiah Thomas endured, Boston Celtics coach Brad Stevens struggled to explain how his star guard managed to elevate his game the way he did against the Chicago Bulls.

On Sunday -- eight days after his sister was killed in an automobile accident -- Thomas rose once more with 33 points and seven assists as the Celtics drew even in their Eastern Conference first-round playoff series with a 104-95 victory.

The best-of-seven series -- tied at two games apiece -- resumes on Wednesday night in Boston. The Celtics have now won two games in a row after falling behind in the series with back-to-back home losses.

Thomas has been a major reason for the comeback.

"What he's been through in the day-to-day is unfathomable the way he has performed on the court," Stevens said. "It's been really incredible."

Either by scoring or with an assist, Thomas helped account for every point of a 12-0 run the Celtics produced in the third quarter after the Bulls took a 65-63 lead. Chicago, which was led by Jimmy Butler's 33 points, erased a 20-point deficit and took its first lead of the game with 4:35 remaining in the third.

But that was when Thomas sparked the offensive surge that pushed the Celtics back to a double-figure lead, and Boston maintained its advantage the rest of the way.

No matter what defender the Bulls threw at him, Thomas -- who re-entered the game in the third quarter with four personal fouls -- couldn't be stopped.

"I just try to play the same way no matter who's out there on the floor (defensively)," Thomas said. "I have a job to do, and that's to score the basketball, make plays for others and be the leader."

Bulls coach Fred Hoiberg, however, took exception to Thomas' offensive style and claimed that Thomas regularly gets away with carrying the basketball.

"He had a hell of a game tonight. But when you're allowed to discontinue your dribble on every possession, he's impossible to guard," Hoiberg said. "He's impossible to guard when you're able to put your hand underneath the ball and take two or three steps and put it back down. It's impossible to guard him in those situations."

Thomas responded: "That's not the reason I'm an impossible cover. I guess (Hoiberg) is just going to continue to say it. I've been dribbling that way my whole life."

As good as he was, Thomas had plenty of help.

Gerald Green scored a playoff career-high 18 points, and Al Horford finished with 15 points and 11 rebounds for the Celtics, who also got 11 points from Jae Crowder and 10 points off the bench from Kelly Olynyk.

While the Celtics won for the second straight time, the Bulls -- despite Butler's effort, which included nine assists -- continued to struggle offensively without injured point guard Rajon Rondo. Nikola Mirotic scored 13 points for Chicago, which also got 13 points from reserve guard Isaiah Canaan and 11 from Dwyane Wade.

The Bulls made a third-quarter push for the second consecutive game, but fell short again, leaving the home team winless in the series. Butler said in each of the past two games, he and his teammates used a lot of effort trying to climb out of a 20-point hole.

"We don't come out with any energy in the first quarter," Butler said. "If we start playing at the start of the game like we do to get out of the hole, we'd probably be up (in the series.)"

Now, after failing to win at home, the Bulls must try to find a way to regain the momentum before Wednesday night.

"It is going to be challenging," Wade said. "Game 1 was challenging; Game 2 was challenging. It's the playoffs. We have to go out there and play basketball better than we did here."

NOTES: Celtics F Gerald Green started for the second straight game in place of Amir Johnson, and Green put up 16 points in the first half. ... Bulls G Rajon Rondo was fined $25,000 for attempting to trip Celtics F Jae Crowder in Game 3. Rondo is out indefinitely with a fractured thumb. "There's always intensity in the playoffs -- that's how it works, that's how it goes," Bulls coach Fred Hoiberg said. "The atmosphere is much more intense, everybody is competing for the same thing, and there's going to be lots of things that happen to ramp up the competitiveness." Rondo said Sunday he plans to appeal the fine. ... Even after struggling to replace Rondo at point guard in Game 3, Jerian Grant made his second straight start. Grant played just five scoreless minutes. G Michael Carter-Williams remained in the rotation, and he played eight scoreless minutes. ... Bulls G Cameron Payne was inactive.