The last time James Harden scored 45 points in a playoff game, it was 2015. His Houston Rockets, down three games to none in the Western Conference finals, were winning a home game for pride against the soon to be champion Golden State Warriors.
On Monday night, Harden matched that career playoff high in a much more significant game.
With the Philadelphia 76ers’ star and N.B.A. scoring champion, Joel Embiid, out with a knee sprain, Harden scored 45 again, and gave the Sixers an unexpected one-game-to-none lead over the top-seeded Celtics, 119-115, at TD Garden in Boston.
Points 43, 44 and 45 were the biggest, coming on a bloodless 3-pointer while closely guarded by Al Horford to give the 76ers a 117-115 lead with just over eight seconds left. On the next play, Marcus Smart of the Celtics threw the ball away in traffic under the basket, and two free throws wrapped it up for Philadelphia.
“I was wondering if they were going to put two on the ball,” Harden said of the possibility of a double-team on the go-ahead shot. “It was a one on one. So then I’m looking up, I’m just, all right, this is what I work on every day. Get the best available shot no matter what it is. Raise up and shoot it.”
Harden made 17 baskets on 30 shots, both season highs. He made seven 3-pointers on 14 shots, also both season highs. He also had a team-high six assists.
From the first possession, Harden, 33, took it upon himself to get Philadelphia points, hitting a 10-foot jumper.
“Whatever they gave me, I rose up and took a shot,” Harden said after the game. “Whether it’s a 3, whether it’s a floater, whether it’s a midrange jumper.”
Asked why there was no double-team on the last shot, Celtics Coach Joe Mazzulla said: “That was one of our best defenders. He made a big shot.”
Paul Reed had 13 rebounds filling in at center for Embiid. He had a career-high 15 in Game 4 of the Sixers’ first-round sweep of the Nets, a game that Embiid also missed.
Going into Monday night’s game, the Celtics were favored not just in the series but to win the N.B.A. title. They were 9.5-point favorites to win Game 1 at home in the absence of Embiid.
Disquietingly for the rest of the series, the Celtics actually played quite well on Monday, hitting 58.7 percent of their shots and outrebounding the 76ers by 10. But they never seemed to be able to stop Harden.
“We have opportunities to bounce back,” a terse Mazzulla said.
After three scoring titles and a Most Valuable Player Award with the Houston Rockets, Harden had built an impressive legacy. But it was tarnished somewhat with an abortive and injury-plagued two seasons with the Nets. When he was traded to the 76ers in early 2022, most of the focus was on the Sixers finally getting rid of Ben Simmons rather on their acquisition of Harden.
Harden has fit in well as Embiid’s lieutenant in Philadelphia. He led the league in assists per game this season with 10.7 and averaged 21 points.
Embiid shot around, but did not run on Monday at practice. Coach Doc Rivers said he didn’t know if Embiid would play in Game 2 on Wednesday.
For one game at least, thanks mostly to Harden, the Sixers didn’t need him.