OKLAHOMA CITY -- After the Memphis Grizzlies were on the wrong side of the most lopsided NBA playoff loss in a decade, Ja Morant kept his message to his teammates short but certainly not sweet.

"We will never play that bad again," Morant said after the top-seeded Oklahoma City Thunder opened their Western Conference playoff series with a 131-80 rout over the Grizzlies on Sunday.

The 51-point margin is the fifth highest in a playoff game in NBA history, according to ESPN Research. It's the most lopsided playoff game in the league since the Chicago Bulls defeated the Milwaukee Bucks by 54 in a 2015 first-round game.

Oklahoma City, which didn't play any of its starters in the fourth quarter, led by as many as 56 points. The record for largest margin of victory in a playoff game is 58, set by the Minneapolis Lakers over the St. Louis Hawks in 1956 and matched by the Denver Nuggets over the New Orleans Hornets in 2009.

"Luckily for us, there's only one way from this, and that's up," said Grizzlies interim coach Tuomas Iisalo, who took the reins when Taylor Jenkins was fired the day after a 125-104 loss to the Thunder on March 27. "We will analyze it, we'll learn from it, and then we will fix those things that hurt us. But there were a lot of things."

A blowout win for the Thunder comes as no surprise, especially considering the circumstances. Oklahoma City broke the NBA record for point differential during the regular season (plus-12.9 per game) while going a league-best 68-14.

The Thunder swept the season series against the Grizzlies, winning each of the four games by double figures. The average margin of Oklahoma City's regular-season wins over Memphis was 18.75 points.

The Grizzlies were also dealing with a difficult schedule against the rested Thunder. Memphis earned the Western Conference's eighth seed by beating the Dallas Mavericks in the final play-in game, which was a 9:30 p.m. ET start on Friday. Game 1 tipped off at noon Sunday at the Paycom Center.

"We kind of have to take this win, like, they're going to be way better in Game 2," said Thunder forward Jalen Williams, who had 20 points, 5 rebounds, 6 assists and 3 steals in 26 minutes. "We're trying to not give them a lot of life in regards to that. That's a really good team over there, so Game 2 is going to be completely different. We're kind of competing with ourselves in a way to make sure we're sharp for Game 2."

Oklahoma City's top-ranked defense smothered Memphis, forcing 24 turnovers, including 14 in the first half. The Grizzlies shot only 34.4% from the floor, including 6-of-34 from 3-point range, although Iisalo noted that Memphis' expected field goal percentage -- a statistic based on the quality of shot attempts -- was significantly higher.

"You got to turn the page fast," said Grizzlies shooting guard Desmond Bane, who was held to nine points on 3-of-12 shooting and had a plus-minus of minus-51 in 27 minutes. "Definitely take the rest of this afternoon and kind of see what we could have done better, but at the end of the day, it's one game. If we lose by 50 or lose on a buzzer-beater, the series is still 1-0. Not the result that we wanted for sure, but still got a good opportunity to get along the road here in two days."

Morant, who finished with 17 points on 6-of-17 shooting, downplayed any effect his sprained right ankle had during the Game 1 rout. He suffered the injury during Tuesday's play-in loss to the Golden State Warriors and needed pain-killing injections to play Friday against the Mavericks.

"It felt good," Morant said, declining to say whether he needed another pain-killing injection before the playoff opener. "I was available."

Oklahoma City coasted to the win despite an off shooting night for MVP front-runner Shai Gilgeous-Alexander. He was 4-of-13 from the floor while scoring only 15 points, three fewer than his lowest total from the regular season, when Gilgeous-Alexander won his first scoring title with 32.7 points per game.

"I have a great group of guys around me," Gilgeous-Alexander said. "I know that, and I've known that for a long time. Tonight is no surprise. They obviously played amazing. A bunch of me's out there tonight might not have won this. That's what you have a team for."