Thanks to a massive 3-pointer by Jaylen Brown that forced overtime, the Boston Celtics defeated the Indiana Pacers 133-128 on Tuesday to open the NBA Eastern Conference Finals.

Indiana, the Cinderella of these playoffs, wasted a great opportunity to win on the road against the top-seeded team from the regular season.

Two turnovers by Tyrese Haliburton (25 points and 10 assists) and Pascal Siakam (24 points and 12 rebounds) allowed Jaylen Brown (26 points) to send the game to overtime with a spectacular 3-pointer from the corner with 5.7 seconds left.

The Pacers were ahead again but Jayson Tatum, the home team's star, scored 10 of his 36 points in overtime to seal the victory at TD Garden.

"We were able to make some plays at the end but we have got to be better to be honest, but I'll take the win," Brown stressed. "We had a lot of ups and downs. I don't think we played at our best level. But the game is fast and there is no time for excuses," stressed the All-Star guard. "You've got to keep going and that's what we did tonight. And we found a way" to win.

The Celtics and Pacers offered a fight worthy of their status as the best offenses of the season.

Indiana, the sixth seed in the conference, already defeated the Milwaukee Bucks and the New York Knicks. On Tuesday, they began their newest challenge, led by Haliburton, Siakam and Myles Turner (23 points and 10 rebounds).

The Pacers did not allow the Celtics to escape at any point on the scoreboard but, after overtaking them in the final stretch, they allowed them to come back with a cascade of individual errors.

"It's a shame because we did so many good things... But this is the playoffs. We have to recover and move forward," said Indiana coach Rick Carlisle, already looking ahead to Thursday's Game 2 in Boston.

'It's the playoffs'

The Pacers started the game with a dynamic completely opposite to that of Sunday's victory in Game 7 against the Knicks.

After making 67.1% of their field goals at Madison Square Garden, a record for a playoff game, Indiana missed its first six shots against the Celtics and quickly found itself down 12-0.

Siakam stopped the bleeding by scoring the visitors' first points after three minutes of play.

The entry from the bench of center Obi Toppin (15 points) and point guard TJ McConnell (13) were key for Indiana to give the game the fast pace they were looking for.

Both teams went to the locker room tied at 57 after a 3-pointer from Haliburton from the center logo at the halftime buzzer.

Tatum and Brown gave Boston a 13-point lead (92-79) towards the end of the third quarter, but the Pacers showed that they never give up and took advantage of Tatum's breaks to equalize again.

Haliburton nailed a second buzzer beater with an acrobatic 3-pointer at the buzzer of the third quarter amid growing nerves from the crowd.

When they had the first win on a platter, Haliburton and Siakam committed two turnovers that allowed Jaylen Brown to force overtime with an off-balance three-pointer from the corner against Siakam

"This is the playoffs. We made a play and it was executed perfectly. I told Jrue [Holiday] that I was going to be open in the corner. And I was and I made it," Brown said later.

Haliburton, who desperately missed the last 3-pointer of the fourth quarter, did hit one at the start of overtime and then converted three free throws to put Indiana ahead 121-123.

But Tatum took a step forward for the home side, who gritted their teeth and pulled out the win. Jrue Holiday (28 points and 8 assists), excellent on both sides of the court, caused another fatal turnover for Haliburton, and Tatum nailed a 3-pointer that sealed the victory at home.

The Western Conference Finals will get underway on Wednesday between Luka Doncic's Dallas Mavericks and Anthony Edwards' Minnesota Timberwolves.