BOSTON -- Isaiah Thomas has 26 games left in what is turning into a historic season for a historic franchise.

Boston's little big man tied John Havlicek's 45-year-old Celtics record with his 40th straight 20-point game, scoring 33 and pulling off his usual fourth-quarter heroics in a 116-108 victory over the Philadelphia 76ers on Wednesday night.

Thomas can break Havlicek's record -- set from Nov. 17, 1971 through Jan. 30, 1972 -- at Chicago on Thursday night in Boston's final game before the All-Star break. He failed to score at least 20 in only one game this season, and has other team records in sight.

Havlicek owns the Celtics mark for points in a season (2,338) set in 1971-72 and Thomas must average 26.2 points the rest of the way to break that record. He's at 29.9 now.

Larry Bird owns the club record for scoring average, 29.9 set in 1987-88. Through Wednesday night, Thomas was at 29.88 points. Bird finished at 29.934.

"I always say it. It doesn't seem real for my name to be mentioned with such greats and Hall of Famers," Thomas said. "It means I'm doing something well. And I'm just glad we're winning on top of it."

As far as the Bird record, he said: "It would mean a lot especially with such great players that played before me. But I'm not aiming for it. If it happens it happens."

Thomas scored 18 in the first half, got to 20 on the first play of the second and scored 11 in the fourth Wednesday. He came in averaging a league-best 10.6 points in the fourth quarter.

"When you know you're getting 20-plus points from a guy on a given night, it's a pretty special trait," Boston coach Brad Stevens said after his team overcame a season-high 22 turnovers to win for the 11th time in 12 games and end the Sixers three-game win streak.

"It's pretty special to know that. He's been amazing with his consistency regardless of how he feels, regardless of little nicks and bruises and everything else. He just kind of keeps going."

Philadelphia's T.J. McConnell, who had 12 points and eight assists, said of Thomas: "He can just score from anywhere. He's a professional scorer and he does that at the highest level. There aren't many people in this league that can stop him."

The Celtics, playing without the injured Avery Bradley and Jaylen Brown, blew an eight-point fourth-quarter lead but turned up the defense as the Sixers also turned the ball over 22 times, many of those down the stretch when Thomas keyed a 10-0 run.

Eight of the turnovers came on Marcus Smart's career-high eight steals.

Smart had 17 points and five assists, Jae Crowder and Kelly Olynyk both scored 16 -- Olynyk with seven rebounds off the bench -- and Amir Johnson 15 for Boston (37-19).

Dario Saric came off the bench to lead the Sixers (21-35 as they hit the break) with 20 points and 10 rebounds, while Robert Covington scored 18 points and grabbed nine boards. Big man Joel Embiid was out with a knee injury.

"I think we are in a good spot," said McConnell, whose team has become competitive. "I'm just frustrated with myself. I wasn't composed down the stretch ... I think as a team we fell apart because of my lack of composure."

Covington left the game in the fourth quarter after hitting his head near the Boston bench diving for a loose ball. Later in the quarter, Gerald Henderson was ejected for two technical fouls on the same call.

The normally sure-handed Celtics, coming off a four-game road trip, turned the ball over on each of their first four possessions of the night, Stevens telling CSN New England: "I told our guys to stay on central time and we played like it -- we started about an hour late."

NOTES: Patriots owner Robert Kraft and DB Patrick Chung were seated courtside and there was a video tribute to the Super Bowl champions in the second quarter. ... F Jahlil Okafor, who missed the last two Sixers games amid trade talk, returned and played 17:07 off the bench, with four points and four rebounds. ... 76ers coach Brett Brown said the team will know more after the All-Star break about when rookie F Ben Simmons will make his NBA debut. "We do expect him to play this year," Brown said, also saying the same thing about injured C Joel Embiid (knee). ... Boston G Avery Bradley missed his 19th straight and 20th in the last 21 games with an Achilles injury. He will not play Thursday when the Celtics visit the Chicago Bulls. ... Brown expressed disappointment G T.J. McConnell was not selected to play in the NBA's Rising Stars Challenge. ... The Celtics observed a moment of silence for former draft pick and player Fab Melo, who died recently. ... Boston brass presented G Isaiah Thomas with his commemorative All-Star jersey before the game.