OKLAHOMA CITY -- The Thunder beat the Memphis Grizzlies 131-80 in Game 1 of their Western Conference playoff series Sunday, the fifth-biggest margin of victory in NBA postseason history.

The 51-point margin was seven points shy of the record and was the largest Game 1 win in NBA playoff history.

Jalen Williams scored 20 points and Chet Holmgren had 19 points and 10 rebounds. Shai Gilgeous-Alexander, the league's scoring champion with nearly 33 points per game, scored just 15. The Thunder still shot 50.5% from the field.

"We played to our identity," Gilgeous-Alexander said. "Nothing more, nothing less than that. We were who we were all year ... and it's going to be the key to our success, just staying true to who we are."

Gilgeous-Alexander had said several times since Oklahoma City's loss to Dallas in last season's Western Conference semifinals that he would be intentional about getting his teammates better prepared for this postseason.

So far, so good.

"I have a great group of guys around me, and I know that," Gilgeous-Alexander said. "And I've known that for a long time. ... They obviously played amazing."

There have been two 58-point playoff margins in NBA history: Denver beating New Orleans 121-63 on April 27, 2009, and the Minneapolis Lakers beating the St. Louis Hawks 133-75 on March 19, 1956.

The Los Angeles Lakers beat Golden State by 56 (126-70) on April 21, 1973, and the Chicago Bulls beat the Milwaukee Bucks by 54 (120-66) on April 30, 2015.

And now, a 51-point game -- where the Thunder had it well in hand by early in the second quarter. It was the sixth playoff victory of at least 50 points.

Sunday's blowout comes just four years after the Grizzlies handed the Thunder a historic beatdown of their own. They beat Oklahoma City by 73 points in a regular-season game on Dec. 2, 2021, setting the record for the largest margin of victory in NBA history.

Game 2 is Tuesday.

The Associated Press contributed to this story.