James Harden hit the go-ahead 3-pointer with 18 seconds remaining in overtime and scored 42 points to help the Philadelphia 76ers stave off a wild comeback by the Boston Celtics in a 116-115 victory Sunday that evened their game-winning series. playoffs at 2-2.

Marcus Smart’s potential winner came too late and the Celtics now head home for Game 5 on Tuesday.

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Joel Embiid of the Philadelphia 76ers takes a shot against the Boston Celtics during the second half of Game 4 in an NBA Eastern Conference semifinal playoff series, Sunday, May 7, 2023, in Philadelphia. (AP Photo/Matt Slocum)

The Celtics rallied from a 15-point deficit with 2 minutes remaining in the third quarter in hopes of taking control of the series.

The Sixers were on the verge of defeat numerous times over the final 17 minutes, none more so than when Joel Embid connected with Smart on a one-handed bench shot with 1:49 to play but was whistled for an offensive foul. The play was reviewed and the call stood. Boston held on to their 112-111 lead with 1:49 left in overtime.

Embiid kept his composure and finally got to the line to make the go-ahead free throws with 59 seconds left and the season on the line.

Embiid had 34 points and 13 rebounds.

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James Harden vs. Marcus Smart

Philadelphia 76ers’ James Harden (1) reacts to Boston Celtics’ Marcus Smart during the second half of Game 4 in an NBA Eastern Conference basketball semifinal playoff series, Sunday, May 7, 2023. , in Philadelphia. (AP Photo/Matt Slocum)

They went into overtime tied 107, all after Smart came up short on a buzzer-beating 3 that was one of the few clutch shots Boston missed in the quarter. The Celtics trailed by 15 points with 2 minutes remaining in the third before taking the life of the Wells Fargo Center.

The fun began when Smart and Jaylen Brown buried back-to-back 3-pointers and Jayson Tatum attacked the rim with a bucket that erased an eight-point hole in 90 seconds. Al Horford put them ahead 98-90, on a possession that started at the other end when Tyrese Maxey blocked his shot, and he swayed at the crowd as he was booed.

Yes, the 76ers had home court, but fans tensed as memories of all those second-round outings since 2001 stirred inside the building. Smart and Malcolm Brogdon hit back-to-back 3s for a 105-100 lead.

Derrick White walks off the court

Boston Celtics’ Derrick White walks court during overtime of Game 4 of an NBA Eastern Conference basketball semifinal playoff series against the Philadelphia 76ers, Sunday, May 7, 2023, in Philadelphia. (AP Photo/Matt Slocum)

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But it was PJ Tucker, the heart and guts of the Sixers, who again did the dirty work with a defensive rebound. He made the free throw with 1:05 left and the tie game gave them new life.