Pascal Siakam hit the game-winning three-pointer in overtime as the Indiana Pacers beat Boston 135-132 on Wednesday, handing the NBA champion Celtics their first loss of the season.

Indiana's win in the second leg of last season's Eastern Conference finals left the Cleveland Cavaliers the East's only undefeated team.

The Los Angeles Lakers had a tough time despite a warm reception for Bronny James in Cleveland, where the Cavaliers dominated with a 134-110 win to improve to 5-0.

In Indianapolis, Bennedict Mathurin led the Pacers with 30 points and 11 rebounds. Siakam added 29 and Tyrese Haliburton scored 17 points with 12 assists for Indiana, which led by as many as 24 points early in the third quarter.

In the fourth period, Boston outscored Indiana 38-24, cutting the deficit to three twice before Jayson Tatum sank a three-pointer with 14.4 seconds left in regulation.

Boston took its first lead since the first quarter when Derrick White hit a layup that made the score 132-130 with 39.7 seconds left.

But Siakam had the final say, scoring a basket to tie the score and then hitting a three-pointer against Haliburton with 7.3 seconds to play.

“It’s big, it’s big,” Siakam said. “We had a few games where we lost due to a few turnovers and rebounds. That’s why we wanted to get this game.”

Tatum scored 37 points, Brown added 25 and White scored 23 for Boston, but they couldn't pull off the miracle.

“We let them come back, but I thought we fought,” Siakam said. “This is what we have to do. We have to be a team that fights until the end.”

Boston fell to 4-1 while Cleveland improved to 5-0 for the third time in franchise history.

Wednesday's game was billed as a homecoming for LeBron and Bronny James – who hadn't played since he came off the bench alongside his superstar father in the Lakers' season-opening win over the Minnesota Timberwolves.

This made them the first father-son duo to play alongside each other in an NBA game.

This time, LeBron James was out for good and the game spiraled out of control when Bronny James came on late in the fourth quarter, to the cheers of Cleveland fans who remember him attending Cavs games as a toddler, as his father The home team played for him.

– Turnovers cost the Lakers –

Although the 20-year-old, who was drafted by the Lakers in June, is expected to soon move to the upstart G League, he scored his first NBA points with a mid-range jump shot.

That will be no consolation for the Lakers.

The Cavs made 17 three-pointers against the Lakers' six-pointers and turned 21 Lakers turnovers into 31 points.

Cleveland took control with a red-hot first quarter, hitting 77.3 percent of its shots from the field.

The Cavs had a lead of 19 at halftime, and turnovers doomed the Lakers' attempts to make significant progress in the third period.

Caris LeVert got a steal from LeBron James and a three-pointer that increased Cleveland's lead to 24 points early in the quarter, and Los Angeles trailed by 20 points heading into the fourth period.

Evan Mobley scored 25 points and Mitchell added 24, while six Cavs players scored in double figures.

LeBron James led the Lakers with 26 points. Anthony Davis added 22 with 13 rebounds, but Los Angeles lost for the second straight year.

The Detroit Pistons, fueled by 23 points from Jaden Ivey and 22 from Cade Cunningham, picked up their first win of the season, defeating Philadelphia 105-95, while the Sixers continued to struggle with stars Joel Embiid and Paul George missing due to injuries.

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