PHILADELPHIA >> James Harden feels more at home in Philly this postseason go-around than he did a year when he was still finding his footing after a trade. It helps that The Beard knows his role alongside Joel Embiid, has his health — and his signature step-back is back on point from beyond the arc.

“He’s confident in how we play now,” coach Doc Rivers said. “Last year, even when he was playing, it was, am I doing the right thing here?”

Harden had all the right moves against the Nets.

Harden hit seven 3-pointers and had 23 points and 13 assists, NBA MVP finalist Embiid scored 26 points and the Philadelphia 76ers pushed back Mikal Bridges and the Brooklyn Nets in a 121-101 Game 1 victory on Saturday.

Tobias Harris added 21 points and the 76ers hit a postseason team-record 21 3s in the opener of this Eastern Conference playoff series. The Sixers are trying to win their first NBA championship since 1983 and advance past the second round for the first time since 2001.

The No. 3-seeded 76ers host Game 2 on Monday.

Bridges scored 30 points and helped the Nets at least hang around in the first half.

But Brooklyn’s starless roster was no match for Embiid, Harden and a playoff-tested roster expected to make a deep run in the postseason. The Sixers had a sellout crowd of 20,913 in a frenzy from the opening tip, then blew the game open in the fourth.

Philly got it done even without a vintage effort from Embiid.

Embiid made only 7 of 15 shots (and all 11 free throws) and was flustered at times against double-teams that followed him all over the court. Embiid was smacked in the face on a missed dunk that sent him crashing to the court in an attempt to draw a flagrant foul. Embiid got heated when he had his arm locked up by Royce O’Neale and the two briefly tussled.

The off-night from the floor wasn’t good enough for Nets coach Jacque Vaughn.

“Hopefully, they’ll be calling traveling and 3 seconds on the big fella the next game,” Vaughn said.

No worries for the Sixers, though. Harden, who topped the league in assists this season, picked up the slack and stuck it to the Nets with his step-back 3s.

Celtics 112, Hawks 99

BOSTON >> Jaylen Brown had 29 points and 12 rebounds, and the Boston Celtics capitalized on a woeful shooting performance by the Atlanta Hawks to hold on for 112-99 victory in Game 1 of the Eastern Conference first-round matchup on Saturday.

Jayson Tatum scored 25 points, 21 in the first half. Derrick White finished with 25 points and 11 rebounds for Boston, which hosts Game 2 on Tuesday.

The No. 2-seeded Celtics led by as many as 32 points, pouncing on an Atlanta team that missed its first 10 3-point attempts and shot 5 of 29 from beyond the arc for the game.

Atlanta used a 32-12 run to cut the deficit to 96-84 on a three-point play by Bogdan Bogdanovic early in the fourth.

The Celtics got the lead back up to 107-87. It was 110-97 with less than two minutes to play when Atlanta’s De’Andre Hunter got free on fast break. But his layup attempt was blocked from behind by Marcus Smart.

Dejounte Murray led the Hawks with 24 points, eight rebounds and six assists. Trae Young added 16 points.

Despite Atlanta’s late push, the Celtics sizzled from all points on the floor, connecting on 13 3 pointers.

After dropping in his third 3-pointer in the closing seconds of the first half, Tatum spread his arms out wide as he backed down the court to a huge ovation from the TD Garden crowd.

Knicks 101, Cavaliers 87

CLEVELAND >> Jalen Brunson shook off foul trouble and scored 21 of his 27 in the second half, Julius Randle returned from an ankle injury to add 19 and the New York Knicks welcomed Cleveland back to the NBA playoffs by holding off the Cavaliers 101-97 on Saturday night in Game 1.

Brunson was limited to nine minutes in the first half, but hit several big shots down the stretch as the Knicks turned back Cleveland’s late rally led by Donovan Mitchell.

Randle was questionable up until pregame warmups, when he tested the left ankle he sprained two weeks ago. The All-Star forward looked like himself while pacing the Knicks, who fell behind 93-92 with 2:12 left.

With Mitchell making plays all over the floor, the Cavs were within 99-97 in the final seconds when Brunson missed a pull-up, but Randle grabbed his 10th rebound and passed to Quentin Grimes, who was fouled with four seconds left.

Grimes made both free throws as the Knicks finished off the Cavs and disappointed a raucous, towel-waving Cleveland crowd that came alive in the fourth quarter when Mitchell scored 14 to bring the Cavs back.

Mitchell finished with 38 for the Cavs, who returned to the playoff stage for the first time since the 2018 NBA Finals. It’s been a long road back for Cleveland, which wasn’t as hurt by its inexperience as lack of bench production from the bench.

Josh Hart added 17 points — and hit a big 3-pointer down the stretch — for New York, whose reserves outscored the Cavs 37-14.

Jarrett Allen had 14 points and 14 rebounds for Cleveland.

Game 2 is Tuesday at Rocket Mortgage Fieldhouse.

Randle missed New York’s final five games after rolling his ankle on March 29, and the injury threatened to derail New York’s playoff hopes. However, he improved this week despite not taking much contact in practice and looked like himself.

Brunson picked up his second foul with 7:52 left in the first quarter, and coach Tom Thibodeau had no choice but to replace the guard, who scored a career-high 48 points against the Cavs on March 31 — the first game Randle missed.

The Cavs didn’t take advantage with Brunson out as New York reeled off 10 straight points and led 30-24 after one.

Brunson was back on the bench with his third foul midway through the second. Again, Cleveland failed to capitalize and the Knicks led 50-45 at half.