Tatum’s scoring output was an N.B.A. record for a Game 7, and it helped send the Celtics to the Eastern Conference finals, where they will face the Miami Heat.

Jayson Tatum turned it on when it mattered and powered the No. 2-seeded Boston Celtics into the Eastern Conference finals with a 112-88 win over the No. 3 Philadelphia 76ers in Game 7 of the Eastern Conference semifinals on Sunday in Boston. Tatum scored 51 points, the record for a Game 7, with 13 rebounds, 5 assists and 2 steals. Jaylen Brown added 25 points and 6 boards.

For the 76ers, their biggest stars again wilted on the biggest stage. Joel Embiid had only 15 points and 8 rebounds, while James Harden had 9 points, 6 rebounds and 7 assists.

The Celtics will face the No. 8-seeded Miami Heat in the Eastern Conference finals, which begins Wednesday in Boston.

Jayson Tatum’s epic Game 7 vs. Sixers started with a mindset shift

BOSTON — Jayson Tatum idolizes Kobe Bryant, who was famous for his maniacal competitiveness on the court.

But to deliver a Kobe-esque performance at TD Garden on Sunday, Tatum adopted the opposite of a Mamba mentality.

“Going into Game 6, it sounds crazy, but I was too locked in,” Tatum told reporters Sunday night after the Celtics’ 112-88 rout of the Philadelphia 76ers in the deciding Game 7 of their second-round playoff series. “I was too tight. I was too in my own head thinking about, ‘What do I need to do? How many points do I need to score?’ It’s a big moment.

“Today, I was more myself. Yesterday and (during) pregame I was relaxed, laughing, joking, and that’s when I play my best: when I’m having fun.”

Celtics Talk POSTGAME POD: Jayson Tatum’s MONSTER Game 7 leads Celtics to blowout over Sixers

While Bryant may not have taken that approach, he would have loved the result: Tatum scored 51 points — the most by a single player in a Game 7 in NBA history — to complete Boston’s series comeback and vault the C’s to their fifth Eastern Conference Finals in seven years.

Tatum’s masterpiece came in the wake of what was almost a series-ending dud in Game 6: The All-Star forward was 1 of 13 through three quarters Thursday before coming alive to score 16 points in the fourth quarter of Boston’s comeback win.

Tatum admitted he was “relieved” to get another chance after the Celtics rallied to win Game 6 and vowed to put less pressure on himself in Game 7 despite the massive stakes.

“At the end of the day, it’s basketball. It’s something that I’ve been doing since I was a kid, something I love to do, and just go out there and relax and have fun,” Tatum said. “When you go out there and relax and kind of think about those days when you were a kid at the YMCA or whatever, the game kind of opens up.

“Just trying not to think about the pressure, what everybody’s gonna say and just focus on the game and having fun. And I think that’s essentially when I’m at my best.”

Tatum had an ally in Joe Mazzulla. After Tatum went a combined 0 for 15 in the first quarters of Games 4, 5 and 6, the Celtics head coach essentially told his best player not to worry about scoring early in Game 7.

“I told him when the game starts, don’t listen to people and try to get out to a good start scoring,” Mazzulla said. “You’re not defined by scoring in my book, and that’s most important: Don’t let your identity get caught up in what others say about you.”

The result was Tatum letting the game come to him instead of forcing difficult shots. He made a concerted effort to attack the paint in the first half, with eight of his nine field goals through two quarters coming on 2-point field goals.

Match Result

After seeing a few shots go down early in Game 7, Tatum went nuclear in the third quarter, drilling four consecutive 3-pointers to outscore the Sixers by himself in the frame (17 to 10) and put the nail in Philly’s coffin.

On the whole, Tatum didn’t have the best statistical series against the Sixers, shooting just 41.7 percent from the floor and 31.9 percent from 3-point range entering Game 7. When he tightened up offensively, the Celtics’ offense stalled, resulting in some of their least efficient games of the season in this series.

A different, freer Tatum emerged Sunday afternoon at TD Garden, however, and he’s the primary reason why the Celtics are preparing to face the Heat on Wednesday night.

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