The Indiana Pacers came into Boston and pushed the Celtics to the brink on Tuesday night in Game 1 of the Eastern Conference finals.

Indiana was up by five with just under two minutes left in regulation, but Boston found a way to force overtime before going on to win 133-128 to open the best-of-seven series on a high note.

Now the top-seeded Celtics will try to win Game 2, something they haven't been able to do this postseason. They failed to go up 2-0 on the Miami Heat in the first round, then had to settle for a 1-1 series against the Cleveland Cavaliers in the semifinals.

"We just gotta be prepared," Boston star Jaylen Brown said. "We know it. We've seen it. We've been hearing it. Now we just have to come out and execute and be better. We will."

Game 2 of the Eastern Conference finals is scheduled for Thursday in Boston.

Jayson Tatum collected a game-high 36 points and 12 rebounds in Boston's Game 1 victory against Indiana. He scored 10 points in overtime, including five straight that gave the Celtics a 127-123 lead with 42.9 seconds to play.

Jrue Holiday added 28 points and Brown finished with 26 for Boston.

Andrew Nembhard canned a 3-pointer to put the Pacers up 115-110 with 1:57 remaining in the fourth quarter, but then the Celtics took over.

Holiday converted a layup and Brown sank two free throws to get Boston within one, 115-114, with 57.4 seconds to go. Nembhard stemmed the tide with a jumper, and Indiana took its 117-114 edge into what was originally supposed to be the game's final seconds.

But Brown knocked down a trey from the corner, knotting things at 117 with 6.1 seconds on the clock. Indiana star guard Tyrese Haliburton missed a 3-pointer at the buzzer, sending the contest to overtime.

Three free throws from Haliburton in the extra session put the Pacers ahead 123-121 with 1:46 left, but Tatum answered with a three-point play, and the Celtics never gave up the lead the rest of the way.

Haliburton had 25 points and 10 assists. Pascal Siakam finished with 24 points, 12 rebounds and seven assists for the sixth-seeded Pacers, who received 23 points from Myles Turner.

"Our guys just need to concentrate on fighting the way they fought in (Game 1) from start to finish, and we'll be back Thursday," Indiana coach Rick Carlisle said. "We did a lot of good things that we need to continue to do. We've been a tough-minded and resilient team, really for almost the entire second half of the year. We have to continue with that and come back in here on Thursday night."

Indiana made 9 of 10 free throws in the game. Boston was 24-for-30 from the foul line.

The Pacers committed 22 turnovers that led to 32 Celtics points.

The Celtics led 34-31 after one quarter, and it was 64-64 at halftime. The Pacers used a 9-0 spurt to pull within four points, 92-88, late in the third quarter, and they trailed 94-93 entering the fourth.

"They scored a lot of points in transition," Brown said. "We gotta clean that up. We want to get them in a half-court game as much as possible.

"Defense is where we have to hang our hat. We have to make sure we execute on defense and the majority of it is transition -- getting back in transition. No layups. Gotta run."

--Field Level Media