LOS ANGELES (AFP) — A resurgent James Harden scored 42 points, including a last-gasp three-pointer to lift the Philadelphia 76ers over Boston, 116-115, in overtime on Sunday to level their National Basketball Association playoff series.

But in Phoenix, not even a career playoff-high 53 points were not enough for Nikola Jokic to spark the Denver Nuggets to a victory over the Suns.

Harden drained a 24-foot corner three with just 19 seconds remaining in overtime at the Wells Fargo Center for a win that leaves the Eastern Conference best-of-seven second round series squared at 2-2.

In a nerve-shredding finale, Boston's Marcus Smart nailed a potential buzzer-beating basket but it did not count as he was unable to get the shot off before time expired.

That left Philadelphia celebrating a gutsy victory that owed everything to the majestic performance of Harden, who bagged his second 40-point game of the series, which continues Tuesday at Boston.

"I put the work in and it was all about being aggressive," Harden said afterward.

"Tonight, it was really do or die."

"We found a way to win and that's all that matters in the post-season."

In the Western Conference, two-time NBA Most Valuable Player Jokic's heroics were not enough as Kevin Durant and Devin Booker each scored 36 to lead the Suns over the Nuggets, 129-124, to equalize their series at 2-2 with Game 5 Tuesday at Denver.

"It's our job to protect home court," Booker said.

"They say a series doesn't start until someone wins on the road so we're going to try to do that in game five."

Jokic could be looking at a suspension after he was issued a technical foul for shoving a spectator, none other than Suns owner Mat Ishbia, after the ball went into the crowd in the first half.

But Booker, who added 12 assists, is fine with Jokic scoring big — if he still loses.