Big third quarter pushes Celtics past Pacers in Game 1

Myles Turner of the Pacers fouls Gordon Hayward of the Celtics during Game 1 on Sunday.

The Boston Celtics became the first Eastern Conference team to live up to its higher seeding by knocking off the Indiana Pacers, 84-74, in Game 1 of their first-round series on Sunday at TD Garden.

Unlike second-seeded Toronto and third-seeded Philadelphia, which were upset in the postseason openers Saturday by Orlando and Brooklyn, respectively, fourth-seeded Boston rallied in the second half for the victory.

Kyrie Irving and Marcus Morris paced Boston with 20 points each. The Celtics shot just 36.7 percent from the field and turned the basketball over 20 times.

“It was hard,” Celtics coach Brad Stevens said. “It wasn’t pretty … you’ve got to stay together, and you’ve got to grind it out.”

In the last 35 seasons, teams that shot that poorly and turned the ball over that many times were just 3-19. The Celtics had to find a way… and they did.

“We just had to turn that page,” Irving said. “It’s the next-play mentality. We weren’t sure or we weren’t doing the right things, but it’s a series. So we come out, any time in the game, runs can happen. Anyone can come in and make an impact and it just doesn’t have to be on the offensive end. Defensively, we call can be in the right spots for each other and really impact and manage the game the way we want to and control the pace.”

The Celtics’ 84 points were their fewest of the season and marked the first time they scored fewer than 100 points and won.

“We held them to 84 points. We just didn’t score enough,” Indiana’s Wesley Matthews said.

Irving playing in his first playoff game since Game 5 of the 2017 NBA Finals with the Cleveland Cavaliers, expected the Pacers to grind away on the Celtics.

“We know how physical they’re going to be. We know that they’re going to reach down, they’re going to slap down,” he said. “They have incredible defenders on their team. They use their length very well. They control the paint. And those guys are very communicative. So we’ve just got to do the right things.

“But getting all those jitters out for the first game, I’m always happy just to get the feel-out game out of the way … now you can really see where you can improve, and where you can take advantage of weak spots.”

Indiana built a 45-38 lead at halftime. According to ESPN’s Stats and Information, the Pacers shot 13 for 20 from the field (3 of 7 from 3-point range) on uncontested shots in the first half, only to see Boston outscore it in the third quarter, 26-8. In the second half, the Pacers shot 3-of-18 on uncontested shots and 0-of-8 from from deep.

“In the third quarter, we started off with two turnovers,” Pacers coach Nate McMillan said. “Then we had open looks that we didn’t knock down, and I thought we lost a little confidence.

“They got the momentum and never let that go.”

Cory Joseph had 14 points off the bench to pace Indiana, while Bojan Bogdanovic was the only other Pacer to reach double figures, scoring 12 points.

“I think what we were doing out there today was good for us,” Pacers forward Thaddeus Young said. We just didn’t make shots in that third quarter.

“That third quarter was huge for them. If you add up all the other quarters, we win. But that third quarter really killed us.”

The two teams will have two days off before playing Game 2 on Wednesday night at TD Garden.