PHILADELPHIA — Better rested and facing a disappointing opponent, the Knicks reversed their fourth-quarter woes and pummeled the Sixers on Tuesday night, 111-99.

The Knicks overwhelmingly won the final 12 minutes as Tom Thibodeau opened up his rotation and Karl-Anthony Towns outplayed longtime foe Joel Embiid.

OG Anunoby scored 24 points and provided the highlight, a soaring dunk early in the fourth quarter that deflated the Philly supporters and energized the traveling Knicks fans.

Josh Hart had a triple-double, finishing with 14 points, 12 rebounds and 10 assists.

The Knicks (5-5) got a balanced attack with their top-6 (starters plus Miles McBride) all scoring at least 14 points despite an off night from Jalen Brunson.

More impressively, they held the Sixers to 37 percent shooting and under 100 points, redeeming themselves after the defensive dud in Indy two nights prior.

It certainly ended positive for the Knicks, but the night took a brief scary turn on the first possession of the second half.

Brunson stepped on defender Caleb Martin’s foot, fell near midcourt and grabbed his right ankle in pain. The point guard bolted to the locker room and missed the next seven minutes of game action.

He returned and finished with 18 points on 5 of 15 shooting.

Thibodeau got some reinforcements and made an adjustment.

After playing with a tight rotation in close games, the coach opened it up from eight to nine players with the addition of Matt Ryan.

Cam Payne also returned from a four-game absence because of a hamstring strain and scored three points in nine minutes.

Ryan was scoreless in nine minutes.

If part of the goal of expanding the rotation was to preserve the starters’ energy in the fourth quarter, it appeared to work.

The Knicks, who had been outscored by 32 points in fourth quarters this season, started the final period Tuesday on an 11-0 run and never looked back.

By the low NBA regular-season standards, Tuesday night had a big-game feel.

First, it doubled as the NBA Cup opener and the court was excessively blue to commemorate Adam Silver’s creation.

Second, it was the season debut of Embiid, who is excessively unavailable and just finished serving a three-game suspension for shoving a reporter.

Third, it was the first matchup between the I-95 rivals since the intense playoff series captured by the Knicks last season.

Both teams underwent seismic shifts in the summer, with Philly signing Paul George and Caleb Martin; and the Knicks landing Towns and Mikal Bridges.

“Obviously both teams have changed quite a bit since those playoffs,” Sixers coach Nick Nurse said. “And they’ve added two guys who can really play. Those guys are both really good players. They both have perimeter games that you have to be mindful of. I guess we’re going to have to see.

“They were going through Brunson pretty much exclusively in the playoffs last year. You’re certainly going to get your dose of Brunson [on Tuesday], but obviously going to get KAT some shots. And they’re doing a pretty good job of spreading it around. Even OG gets his moments and they go through him a little bit, too. They are much more balanced, they’re trying to be more perimeter oriented. We have to see.”

Nurse saw Embiid sludge through 26 minutes with 13 points on 2 of 11 shooting.

He saw Towns destroy Embiid while grabbing 13 boards with six assists and 21 points.

He saw Philly’s starting backcourt, minus the injured Tyrese Maxey, shoot a combined 2-for-11.

Nurse saw his Sixers (2-8) continue to stand with Milwaukee as the biggest disappointments in the East.

The Knicks took advantage with a stout defense and a big fourth quarter.