The Oklahoma City Thunder pulled away late to beat the Los Angeles Lakers 125-107 in an NBA playoff thriller, taking a commanding 2-0 lead in their best-of-seven Western Conference semifinal series.

Shai Gilgeous-Alexander, the reigning NBA Most Valuable Player and finalist for the award this season, scored 22 points and the Thunder capitalised on 21 Lakers turnovers on Thursday to hand LeBron James a defeat in his 300th career playoff game.

Elsewhere, Eastern Conference top seeds Detroit are also up 2-0 after a 107-97 home win over the Cleveland Cavaliers.

In Oklahoma City, Gilgeous-Alexander was again below his best, but he was amply supported.

Chet Holmgren scored 22 points and pulled down nine rebounds, Ajay Mitchell added 20 points, and Jared McCain delivered 18 points off the bench to help the Thunder withstand a 31-point performance from Austin Reaves.

James, who became the first player to contest 300 postseason games, scored 23 points and handed out six assists, and the Lakers led by five points early in the third quarter.

But with league-leading scorer Luka Doncic still sidelined by injury, the Lakers could not hang on, even with Gilgeous-Alexander on the bench for considerable stretches because of foul trouble.

Oklahoma City produced a 22-5 scoring run to seize control and will aim to keep the pressure on when the series shifts to Los Angeles for games three and four on Saturday and Monday.

“We’ve got to be the aggressor,” Gilgeous-Alexander said. “I feel like they were playing with more force, they were attacking harder, making quicker decisions, playing with a better sense of urgency, especially in the first half.

“As long as we take care of that, we should have our foot in the right direction.”

A bruising contest saw both teams irked by the officiating. Gilgeous-Alexander was whistled for a flagrant foul, and both he and James were sprawled out under the basket after a foul by Reaves late in the game.

Lakers coach JJ Redick took issue with the officiating, saying the Thunder “have a few guys who commit a foul on every possession”.

But, he added, “We didn’t lose because of the refs.”

Cunning thrives in ‘high-stakes’ situation

In Detroit, Cade Cunningham scored 12 of his 25 points in the fourth quarter and handed out 10 assists to lead the Pistons.

They set the defensive tone early but had to rally late after the Cavaliers battled back to take a two-point lead early in the fourth quarter.

“I just want to win games,” Cunningham said of his dominant fourth-quarter performance. “It’s been a lot of games down the stretch where it’s tight … The ball is in my hands and I’ve got to make plays with it.

“The pressure and the moment, it’s high stakes … all of that stuff fuels me.”

Cleveland’s Donovan Mitchell scored a game-high 31 points. Jarrett Allen chipped in 22, but James Harden had just 10 on three-of-13 shooting, and his four turnovers included a costly giveaway in the final minute.

The Cavaliers have a mountain to climb as they head home for game three on Saturday and game four on Monday.

The Pistons, who locked up the top seed in the East with the third-best record in the league, had to fight back from a 3-1 deficit to beat the Orlando Magic in the first round.

In this series, they were determined to hold on to home-court advantage, and game two featured another lockdown defensive display from Detroit, leading to a 54-43 halftime lead.

The Cavaliers responded in the third quarter and took the lead on Evan Mobley’s dunk minutes into the fourth – their first lead since the opening minutes.

But they could not hang on. A Duncan Robinson three-pointer put Detroit back in front, and they would not trail again.

Cunningham said the Pistons will have to “turn up our energy even more” in Cleveland.

“They’re a tough team to beat at home,” he said.