PHILADELPHIA -- The Boston Celtics are missing Gordon Hayward and two other key players. But when it mattered most Friday night, Kyrie Irving most certainly was not missing.

Irving scored seven of his 21 points in a game-ending 18-8 run as the short-handed Celtics beat the Philadelphia 76ers 102-92 for their first victory of the season.

Asked about his late surge, Irving fairly shrugged.

"Come on, man," he said. "That's winning time, man."

Al Horford added 17 points and nine rebounds for Boston, which lost Hayward, their newly acquired forward, to a dislocated left ankle and fractured tibia in Tuesday's opener in Cleveland. He is expected to miss the entire season.

The Celtics (1-2) were also without starting guard Marcus Smart, who sprained both ankles in Wednesday's home opener against Milwaukee, and forward Marcus Morris, who is out with a sore left knee.

"Like I said before -- excuse my language again -- but (stuff) happens," said Irving, who came to Boston in an offseason trade with Cleveland. "This is the league we all signed up for."

He called it a gutsy win. Horford did not disagree.

"It just felt good to get a win," he said. "I know that it's a long season and everything, but we played two really tough games, lost them both. A lot of emotions going on in our locker room. We needed this. We needed to get it going."

Rookie Jayson Tatum added 15 points and Terry Rozier scored 14 off the bench for Boston, which outscored Philadelphia 33-20 in the fourth quarter and 46-27 in the last 16:20 to erase a nine-point deficit.

"We let one go," Sixers coach Brett Brown said. "We were up (nine), I think, in the third period and you felt like with a few more baskets that they might have gone away. I give the Celtics credit, but I really feel like we let one slip."

Horford's basket with 6:48 left snapped an 84-84 tie, and Tatum added a jumper to put Boston up by four. Irving then sandwiched two jumpers around a layup by Philadelphia's Robert Covington to make it 92-86.

With 1:34 left and the Celtics leading 95-90, Irving drew a foul from Jerryd Bayless on a 3-point attempt. He made all three free throws to give Boston a 98-90 cushion.

J.J. Redick scored 19 points and Bayless added 18 for the Sixers (0-2). Joel Embiid had 11 points and 14 rebounds but missed his first eight shots and finished 4 of 16 from the floor. Rookie Ben Simmons had 11 points, 11 rebounds and five assists.

Philadelphia went 6:43 without a field goal beginning midway through the first quarter, enabling Boston to go up 29-21 early in the second.

The Sixers drew even courtesy of their 3-point sniping. They made four in the opening minutes of the second quarter, the last by Redick to forge a 37-37 tie.

Boston surged back in front, but Simmons notched the first five points in a 7-0 run at the end of the half, putting Philadelphia ahead 50-46.

Simmons had nine points and eight rebounds in the half, and Irving topped the Celtics with 12 points.

The Sixers also tacked on the first five points of the second half to go up by nine, and they maintained the lead the rest of the third quarter. The Celtics did close the gap to 72-69 on a tip-in at the buzzer by Aron Baynes.

Boston assumed its first lead of the half at 82-80 on Horford's 3-pointer with 8:04 left. The score was tied on two more occasions before Horford's jump hook from the right baseline with 6:48 remaining put the Celtics ahead to stay at 86-84.

NOTES: Boston coach Brad Stevens said F Gordon Hayward, who underwent surgery on Wednesday, left the hospital. In his absence, Stevens said, there will be "significant tweaks" to the Boston offense -- that the Celtics will run more of it through the post than originally planned. ... Sixers coach Brett Brown said a decision has not yet been made as to whether C Joel Embiid will play Saturday night in Toronto. Embiid, who missed his first two seasons because of foot injuries, did not play the second game in back-to-back situations before he was lost to a knee injury last season. This year, Brown said, the medical staff will weigh the number of minutes Embiid plays, as well as how taxing those minutes were, before rendering a verdict "in consultation with Joel."