Boston’s Jayson Tatum directs a play during Game 5 of the Eastern Conference finals Friday night against the Miami Heat in Lake Buena Vista, Fla. Tatum scored 31 points to lead the Celtics to a 121-108 win. Mark J. Terrill/Associated Press

LAKE BUENA VISTA, Fla. — His team’s season saved for at least two more days, Boston Coach Brad Stevens offered the most succinct assessment of his Celtics.

“We’re prideful,” Stevens said.

Celtic Pride. It was on display Friday night – when Jayson Tatum and his teammates announced very loudly that they’re not ready to see the world that exists outside the NBA’s restart bubble quite yet.

Tatum had 31 points and 10 rebounds, Jaylen Brown added 28 points and the Celtics shook off a slow first half to top the Miami Heat 121-108 in Game 5 of the Eastern Conference finals and stave off elimination.

“Our deal was to come out and play, come out and compete, give it our best shot and I thought we played pretty well in the second half,” Stevens said. “But we’re going to have to do it again and again because of the position we’re in.”

The Heat lead the series 3-2, with Game 6 on Sunday.

Daniel Theis had 15 points and 13 rebounds for the Celtics, who trailed by 12 early but took control with a big third quarter. Kemba Walker scored 15 points, Marcus Smart added 12 and Gordon Hayward had 10 for the Celtics.

Goran Dragic scored 23 points before fouling out with 4:27 left for Miami, which got 20 points from Duncan Robinson.

“It’s certainly not going to be easy,” Robinson said. “We’ve got to band together to do difficult things.”

Jimmy Butler scored 17, Tyler Herro and Jae Crowder each had 14 and Bam Adebayo 13 for the Heat – which could get nothing to fall from 3-point range.

Miami was 7 for 36 from beyond the arc and is now shooting 24.8% on 3s in its last 13 quarters, after shooting 38.3% in the playoffs before its drought.

“Boston played great in that second half,” Heat Coach Erik Spoelstra said. “They deserved and earned what they got. We understand how tough it is to win in the playoffs. We did not compete hard enough defensively and we paid the price for that. But you do have to credit Boston. They played with great force.”

Brown made back-to-back 3s in the fourth quarter to turn an eight-point lead into a 103-89 margin with 8:05 left.

He turned a blew a kiss to the Heat bench after the second one, reminiscent of something Herro did during his 37-point barrage in Game 4.

Game on. Series on.

“It’s not going to be perfect,” Tatum said. “You just want to give yourself a chance.”

The opening minutes didn’t go according to plan for Boston, which missed 11 of its first 12 shots, committed four turnovers and got into a 17-5 hole very early.

But they weathered all that and, even after shooting only 40% in the first half, Boston trailed 58-51 at the break – never leading, but never letting Miami get too far removed from view.

The Heat scored the first basket of the third quarter. The next few minutes were all Celtics.

They went on a 13-0 run over a stretch of only 3:06 to turn a nine-point deficit into a 64-60 lead, and the game changed just that fast. A separate 7-0 burst followed, Walker connected on a 3-pointer with 4:26 left for a 77-67 edge – Boston’s first double-digit cushion of the night – and the Celtics eventually led by 14 before settling for a 92-83 lead going into the fourth.

“In all sincerity, first time I’ve seen Celtics basketball in the last few games,” Stevens told his team during a timeout.

And it was good enough to ensure that Friday wouldn’t be the last time he’d see Celtics basketball this season.

TIP-INS

Heat: Adding to the woes of the third quarter was this – Miami was outrebounded 16-5 in those 12 minutes. … With their fourth 3-pointer Friday, by Robinson with 47 seconds left in the first half, the Heat passed the 2017-18 Golden State Warriors (1,161) for 14th place on the single-season 3s list. Next up: The 2016-17 Warriors, who had 1,198.

Celtics: Not that any of this should count on a neutral floor, but Boston ended what officially goes down as a five-game “home” losing streak. … The Celtics are 2-0 when facing elimination games this season. The last time Boston won multiple elimination games in the same season was 2008, when it prevailed in first- and second-round Game 7s and went on to win the NBA title.

GOOD THIRD

This was the 18th playoff game in Celtics history where they scored at least 41 points in a quarter – and probably not surprisingly, they’re 18-0 in those games. It has happened in 20 different quarters; they did it in three separate quarters in a 157-128 win over the Knicks on April 28, 1990.

BAD THIRD

The only other time Miami allowed 41 points in a postseason quarter was June 10, 2014, when the Heat were outscored 41-25 in the first quarter of Game 3 of that season’s NBA finals against San Antonio. Coincidentally, Friday’s third-quarter debacle had the same score: 41-25.