Cool as their unflappable head coach, Brad Stevens, the Boston Celtics never got down even as their deficit ballooned against the young and athletic Minnesota Timberwolves.

When the Celtics finally got going, the Wolves tensed up once again and let another big lead get away.

Isaiah Thomas scored 29 points and Boston rallied from 13 points down in the fourth quarter to beat the Timberwolves 99-93 on Monday night.

Al Horford added 20 points, six rebounds and five assists for the Celtics, who trailed 81-68 after three. Boston opened the fourth on a 17-0 run to take the lead and held on down the stretch for its second straight win.

“I think give us credit for playing a little harder than them and making them think a little more and getting them uncomfortable,” Thomas said.

Karl-Anthony Towns had 27 points and 18 rebounds for the Timberwolves. Gorgui Dieng added 20 points and 10 rebounds, but Andrew Wiggins was just 5 for 18 and Minnesota scored three points in the first 9 minutes of the fourth.

“We laid a damn egg,” said Zach LaVine, who was 4 of 12 from the field and 0 for 7 on 3-pointers.

Terry Rozier added a career-high 12 points off the bench and keyed the Celtics’ surge in the first 6 minutes of the fourth.

The Timberwolves have normally reserved their meltdowns this season for the third quarter, when they have the NBA’s worst point differential. But they won that period 29-26 on Monday night, just the second time this season they have outscored their opponent in the third.

Jonas Jerebko and Rozier opened the fourth with 3-pointers, and Rozier added another long ball and a steal and dunk to push the Celtics in front.

Towns was the only player who scored for the Wolves in the first 11 minutes of the fourth quarter, converting a three-point play with 5:18 to go for their first bucket and hitting a 3-pointer with 2:38 remaining.

Boston outscored Minnesota 31-12 in the fourth as the Timberwolves shot 5 for 25.

“They were definitely pressing,” Celtics guard Marcus Smart said. “Guys were into guys, we were making everything hard. You could definitely tell they were pressing to find a great shot.”

The Wolves outscored Boston 58-34 in the paint and outrebounded the Celtics 51-39, including 16-6 on the offensive glass. But Minnesota missed eight free throws.

“I think we have to play tougher with a lead,” coach Tom Thibodeau said. “And the big thing for us is to improve and learn.”

Tip-ins

Celtics: Horford also had three blocks and reached 20 points for the first time with the Celtics. … Boston was issued a rare delay of game warning coming out of a timeout late in the third quarter. … Jerebko was a plus-20 in under 19 minutes.

Timberwolves: Minnesota entered the game leading the NBA in 3-point shooting, but was 4 for 24. … Towns has blocked a shot in 20 straight games. … F Brandon Rush was active after missing the previous seven games with a sore big toe on his right foot. He played 2 minutes in the fourth quarter.

Tempers flare

One of the biggest guys on the court and the smallest got into it in the third quarter when the 6-foot-11, 240-pound Dieng leveled the 5-9, 185-pound Thomas with a screen. Dieng was called for an offensive foul because he was moving while he set the screen, and Thomas took exception. The All-Star guard got up and shoved Dieng, and the two exchanged words while being separated by teammates.

“It was the heat of the battle,” Thomas said. “We talked about it after, and he loves my game, I love his, so we’re good.” 

Crowder ailing

Jae Crowder missed eight games with a sprained left ankle before returning on Saturday against Detroit. He made life difficult on Wiggins, who was 0 for 5 from 3-point range. But Crowder had to leave the game in the third quarter because of soreness in that left ankle and did not return.

“Hopefully he’ll be OK,” Stevens said.

Up next

Celtics: Boston wraps up a three-game road trip in Brooklyn on Wednesday night.

Timberwolves: Minnesota starts a three-game trip with a game at New Orleans on Wednesday night in which Towns will face fellow Kentucky big man Anthony Davis.