Tobias Harris flipped on his postseason switch.

As a result, the 76ers are leading the Washington Wizards, 1-0, in the best-of-seven opening-round playoff series.

The power forward carried the Sixers in the first half with Joel Embiid in foul trouble. Then he continued to make several clutch baskets before Embiid took over late as the Sixers held on for a 125-118 victory at the Wells Fargo Center Sunday afternoon.

Harris finished with a postseason career-high 37 points, while Embiid added 30.

Harris’ previous postseason-best was 29 points, which came against the Brooklyn Nets in Game 3 of an opening-round series on April 18, 2019. He nearly had that many points in the first half of Sunday’s matchup, scoring 28.

“You have nights like this and you get in those types of rhythms with the work that’s put in,” said Harris, who also finished with six rebounds, two assists, and two steals. “I would say like the past two, three months, I’ve been preparing for this type of moment, preparing myself.

“And just telling the team as well, this is the nitty gritty, this is the playoffs.”

Twenty-one of Embiid’s points came after intermission. With the Sixers up, 115-108, with 3 minutes, 8 seconds remaining, Embiid scored their next eight points. His final two gave the Sixers a 123-116 lead with 14.1 seconds left. Harris then added a pair of foul shots with 7.1 seconds remaining to give Philly a seven-point victory.

“Embiid made every shot that was needed,” Wizards coach Scott Brooks said of what enabled the Sixers to pull away in the second half. “They were contested. We did a few different things defensively on him.

“Great players are great. They can figure things out.”

However, this victory didn’t go without a little controversy.

Russell Westbrook was called for stepping out of bounds with the Wizards down five with 37.1 seconds left. Washington challenged the call, as the point guard’s heel was elevated. Westbrook and the Wizards felt the heel, which was out of bounds, never touched the court.

“The camera angle I saw, it was like the Sean Elliott play,” Brooks said. “They obviously looked at a bunch of different angles and they called what they called.”

As a San Antonio Spur in 1999, Elliott hit a three-pointer with his heel close to the line to help win the game. The play was called the Memorial Day Miracle.

But on Sunday the ruling stood.

“In the conversation with the replay center official, there was not enough evidence to overturn the on-court ruling,” crew chief Eric Lewis told the pool reporter.

Asked if his heel touched the sideline, Westbrook responded, “It [doesn’t] matter now. It doesn’t matter.”

Westbrook finished with six turnovers rebounds to go with 16 points, 14 assists, and five rebounds, while shooting 7-for-17 from the field. The Wizards were paced by Bradley Beal’s 33 points to go along with 10 rebounds. Beal also finished with six turnovers.

With Beal heating up and Washington shooting 55.7% from the floor, the Sixers needed all of Harris’ and Embiid’s points to win what amounted to a dogfight. The eighth-seeded Wizards led at the half and never gave the top-seeded Sixers a breather.

Seth Curry added 15 points, all in the second half. The shooting guard buried three huge three-pointers in third quarter. Ben Simmons finished the game with six points, and career-playoff highs of 15 rebounds and 15 assists.

» READ MORE: Ben Simmons joins Wilt Chamberlain as only Sixers with at least 15 rebounds and 15 assists in a playoff game

But there was no denying that Harris was a major reason why the Sixers avoided an opening-game upset. He carried his team in the first half with Embiid on the bench, saddled with three fouls.

“It was huge, especially in that time,” Embiid said. “When I was on the bench, we needed his scoring. You know, he showed up the whole game really, but especially in that first half. ... That was huge for us.”

Harris’ 28 first-half points came on 12-of-19 shooting. That was big for the Sixers with Embiid playing only 10:25 in the first half.

While Harris was on fire, the Sixers made only 3 of 17 first-half three-point shots. The Sixers’ poor outside shooting combined with Embiid’s absence contributed to the Wizards leading, 62-61, at the break. Washington shot 60% in the second quarter.

But this wasn’t the first time Harris stepped up in Embiid’s absence.

The 10th-year veteran had success as the team’s go-to guy while Embiid was sidelined 21 games this season due to injuries, illness and rest.

“He goes out with three fouls and it was just the same mentality that we have to get this thing rolling,” Harris said. “Opportunities were there for me to be aggressive and get to my spots and get the shots that I wanted to get.”

Curry caught an elbow in the torso late in the first half and headed to the locker room. He returned at the start of the second half.

The Sixers found a good rhythm in the second half while being focused on trying to step up their defense.

“We know what’s the blueprint to our success,” Harris said. “In Game 2, we have to bring even more of that.”

Game 2 will be at 7 p.m. Wednesday at The Center.