BOSTON (AP) — As the Celtics were taking control of their playoff opener against the Orlando Magic, Boston’s best player was on his back in pain and tugging at his wrist.

As chants of “MVP!” rained down on him, Jayson Tatum eventually rose to his feet and was loudly cheered as he paced toward the bench.

“I just landed on it. It was throbbing for a second,” Tatum said. “It kind of went away.”

And brought a sigh of relief for a Boston team just starting its quest to repeat as NBA champions.

Derrick White scored 30 points, Tatum had 17 points and finished the game after a scary late fall, and the Celtics beat the Magic, 103-86, in Game 1 of their first-round playoff series Sunday, April 20.

Payton Pritchard added 19 points off the bench for Boston, which hosts Game 2 on Wednesday night. Jaylen Brown played 31 minutes and had 16 points on 6-of-14 shooting after missing the final three games of the regular season due to a lingering knee issue.

“We’ve got many different ways we can win. A lot of different things we can throw at teams,” White said.

With Boston leading 89-73 with 8:28 remaining, Tatum went up for a dunk and was hit hard by Kentavious Caldwell-Pope as he tried to block it. Tatum landed awkwardly on his right side.

He stayed down briefly before eventually rising to his feet, clenching his right hand. After a video review by referees, Caldwell-Pope’s foul was upgraded to a flagrant foul. Tatum subsequently missed the two ensuing free throws but remained in the game. He said a postgame X-ray came back clean.

Paolo Banchero led the Magic with 36 points and 11 rebounds. Franz Wagner added 23 points for Orlando, which has not made it out of the first round of the playoffs since the 2009-10 season.

Orlando led by a point at halftime, limiting a Boston team that set an NBA record for 3-pointers this season to 7 of 15 from beyond the arc in the opening 24 minutes and 16 of 37 for the game.

Meanwhile, The Oklahoma City Thunder beat the Memphis Grizzlies, 131-80, in Game 1 of their first-round Western Conference playoff series, 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.

Aaron Wiggins scored 21 points, 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.

In Cleveland, Donovan Mitchell quickly put any doubts to rest about whether his left ankle was 100% going into the playoffs for the Cavaliers.

Mitchell scored 30 points and tied a playoff career high with four steals and the Cavaliers beat the Miami Heat, 121-100, in Game 1 of the Eastern Conference first-round series.

“He can get in the lane and finish and he’s a great shooter. Such a complete player,” Cavaliers coach Kenny Atkinson said. “Whatever we ask him to do, he’ll do it. He never shies away when we ask him to do the dirty work.”

It was the seventh straight series where Mitchell has scored at least 30 points in Game 1, tying Michael Jordan, who had two streaks of seven games.

“Just setting the tone. I have to be aggressive and see how the defense reacts to me,” Mitchell said.

Earlier, Stephen Curry scored 31 points and the Golden State Warriors built a huge lead and held on to beat the Houston Rockets, 95-85, in Game 1 of the first-round playoff series.

The seventh-seeded Warriors led by 23 in the third quarter, but second-seeded Houston cut it to 69-60 entering the fourth.

A basket by Amen Thompson with about 5 1/2 minutes remaining got the Rockets four. Curry hit his fifth 3-pointer of the night a few seconds later to make it 82-75.