CHICAGO -- When his mesmerizing Game 4 performance was complete, Boston Celtics guard Isaiah Thomas ventured to his postgame news conference, during which a reporter relayed how Chicago Bulls coach Fred Hoiberg had made comments suggesting that part of Thomas' success stemmed from the fact that referees don't whistle him for routinely discontinuing his dribble.

Thomas smiled and started, "That's not the reason why I'm an impossible cover."

The confident rebuttal was enough to elicit hearty laughter from Thomas' two young sons, James and Jaiden, seated next to him on the riser. "It's not that funny," Thomas told his kids, bringing laughter from reporters.

The Bulls surely were not laughing at the way Thomas took over the final five minutes of the third quarter of Sunday's Game 4. Thomas either scored or assisted on all 16 points Boston scored over the final 5:12 of the third frame, helping the Celtics re-establish a lead after the Bulls had rallied from 20 points down to briefly pull ahead.

Thomas routinely probed his way to the basket, dribbling through a sea of white jerseys, to either finish a layup in traffic or draw a foul near the hoop. When the defense did build a wall in front of him, Thomas was able to feed teammates for open looks.

"Not one man can guard me," Thomas said after Boston's 104-95 triumph at the United Center. "And that's just the confidence I have, but also my coaching staff and my teammates put me in position to be successful. No matter what other teams are doing, [Coach] Brad [Stevens] figures it out and puts me in the position to be the best player I can be, and my teammates allow me to do that, as well."

After the Bulls pulled ahead 65-63 with under five minutes to go in the third, Thomas went to work. Dribbling off a screen from Al Horford, Thomas lost his defender while racing toward the sideline, then cut back hard toward the paint. Jimmy Butler and Robin Lopez tried to chase him as Thomas gained speed downhill. Both Nikola Mirotic and Lopez leaped to challenge Thomas near the rim, but he maneuvered the ball back across his body and finished on the right side of the rim as the two Bulls bigs flew the opposite way.

There was a similar drive a short time after in which Thomas muscled home a left-handed layup while drawing contact from Mirotic underneath the basket. Teammates flexed their muscles and pointed at Boston's 5-foot-9 guard from the sideline as play went back up the court.

Thomas finished with 33 points overall on 10-of-21 shooting with seven assists. He was plus-17 over 35 minutes, 48 seconds of floor time. His efforts helped the Celtics even the best-of-seven, first-round series at 2-2.

Maybe the most remarkable part of Thomas' third-quarter outburst was that it came with four fouls. But as the Bulls made their charge, erasing an 11-point halftime deficit in little more than six minutes, Celtics coach Brad Stevens had no choice but to put Thomas back in the game while hoping to end one of Boston's familiar painful scoring lulls without Thomas (Boston was minus-8 in Game 4 when Thomas was on the bench).

Thomas looked completely unfazed and undeterred by his foul trouble. The Celtics closed the quarter on a 16-5 run, which was enough to keep the Bulls at arm's length in the final frame.

"We were just going to spread the floor out, give [Thomas] space and let him create," Jae Crowder said of Boston's third-quarter run. "At the time we felt like they didn't have an answer for that. ... [Thomas] gets in a zone like that, he scores at will."

Added Avery Bradley: "As a team, I know it helps us feel a lot more confident when he's on the floor."

Sunday's game was the first time Thomas addressed reporters following the death of his younger sister, Chyna, on April 15. Thomas requested only basketball-related questions but hinted occasionally at the emotional turmoil he's enduring.

Stevens said it's "unfathomable" what Thomas is going through and marvels at his ability to play to the level he has in this series given all the emotions he's enduring. Teammates have tried to help Thomas cope with his loss and have been excited to see him smiling more in recent days.

Basketball has been Thomas' sanctuary, a three-hour diversion from trying to come to grips with the death of his sister following a single-vehicle crash.

Thomas' face lit up when talking about his friend Gerald Green, the veteran who has given Boston an unexpected spark after elevating to a starting role in Boston's new small-ball starting five. Green scored 16 of his 18 points in the first half of Sunday's win, helping Boston push its lead as high as 20 before the intermission.

But it was Thomas' efforts that might have saved the Celtics' season after the Bulls rallied ahead. If Boston doesn't fight back at that point, Chicago emerges with a 3-1 series lead and pushes the Celtics to the brink of elimination.

Instead, Boston packs all the momentum heading to Boston. The loss of Rajon Rondo has left the Bulls unsteady at the point guard position and changed the tenor of the series even before Boston's Game 3 triumph on Friday.

Boston will have home-court advantage for crucial Game 5, though the road team has won all four games in this series. ESPN's Basketball Power Index gives Boston a 69 percent chance to prevail in what's now a best-of-three.

Even BPI's super-computer can't quite calculate how valuable Thomas is to Boston's success. That Hoiberg needed to vent in the aftermath is only a reflection of how difficult it is for opposing teams to slow Thomas.

Yes, when Thomas gets going, it's no laughing matter for the opponent.