Everything goes wrong for the Sixers, including the confetti

But a premature celebration at Wells Fargo Center on Saturday night quickly turned into an all-consuming nightmare for the 76ers when the Boston Celtics emerged with a 101-98 victory in overtime to take a three-games-to-none lead in their Eastern Conference semifinal series. Game 4 is Monday in Philadelphia.

The 76ers were hoping to gain some traction in a best-of-seven series that had already turned lopsided with two losses in Boston, and they had opportunities here. So many of them, in fact. But they also seemed oddly determined to offset each with a turnover or a mental gaffe, and the Celtics’ Al Horford made them pay.

Horford made a go-ahead layup with 5.5 seconds left in overtime, then sealed the win when he stole the ensuing inbounds pass and was fouled. He made both free throws.

“It was intense,” said Horford, who finished with 13 points. “These are the kind of moments you want to be in as a basketball player.”

The game will also be known for confetti — extraordinarily untimely confetti. In the final moments of regulation, the 76ers’ Marco Belinelli made a long 2-pointer that tied the score, 89-89, sending it to overtime. Brown initially thought the shot was a 3-pointer — “I actually left the court,” he said — and so did a contractor who was operating a confetti cannon along one of the sidelines. The cannon spewed confetti everywhere. Arena employees scrambled to clean it up. The Celtics, who awaited overtime, considered it confetti karma.

“Everything happens for a reason,” point guard Terry Rozier said.

The confetti guy was not the only person who had a lousy day at the office. Ben Simmons, the 76ers’ first-year point guard, labored through another series of growing pains. After blowing a dunk late in the fourth quarter, he missed on a put-back with 17.2 seconds left in overtime when the 76ers could have stalled with the lead.

“I’ve got a wide-open shot that I make a lot of the time, and I missed it,” he said.

Simmons, who was otherwise solid, collecting 16 points, 8 rebounds and 8 assists, punctuated his set of late-game miscues by throwing the inbounds pass that Horford stole.

Belinelli launched a 30-footer at the buzzer that caromed long.

Joel Embiid finished with 22 points for Philadelphia, and J.J. Redick added 18. The playoffs have been an entirely new experience for many of the 76ers.

“Joel’s going to learn a lot,” Brown said. “Ben’s going to learn a lot. It’s painful admitting that now, but there’s a lot of truth to that.”

The Celtics, meanwhile, are surging through the playoffs with a roster pockmarked by injuries. No Gordon Hayward. No Kyrie Irving. But they do have precocious stars like Jayson Tatum (24 points) and Jaylen Brown (16 points, 9 rebounds), who are playing with a sort of confidence that belies their inexperience.

The 76ers had crammed as much of Philadelphia as they could inside the arena for Game 3. Their fans booed the Celtics during warm-ups. They screamed unpleasant things during player introductions. Nick Foles, who recently quarterbacked the Philadelphia Eagles to a win in the Super Bowl, came out before the game so he could bang on a big bell at center court.

It was, in other words, a hostile environment for the Celtics, who also — and this should not be overlooked — had to contend with the 76ers themselves.

But nothing seemed to affect the Celtics — not the fans, not the confetti, not their defenders. Now, they are one win from an improbable trip to the conference finals.

This article originally appeared in The New York Times.