BOSTON — Brad Stevens didn’t fret when he saw Isaiah Thomas come off the bench and miss his first four shots to end the first quarter.

And the Boston Celtics coach didn’t want his little guard to stop shooting, either.

“We’ve talked quite a bit about that — play with speed, play aggressive, play with spirit, let the chips fall where they may,” Stevens said after Thomas went on to contribute 27 points and seven assists in just over 29 minutes, leading Boston to a 112-95 victory over the young and undermanned Philadelphia 76ers in the opener for both teams on Wednesday night.

Asked if he doesn’t mind when a player like Thomas runs cold, Stevens said, “No, because a hot streak is coming. Law of averages … analytics (smile).”

Thomas, who battled injuries during training camp, said, “That’s my job. I’m not going to be shy when I got a job to do out there. Coach has confidence in me. My teammates have confidence in me, and they tell me to continue being aggressive — so I’m going to continue to do that.”

The loss spoiled the NBA debut of center Jahlil Okafor, the third overall pick in the 2015 NBA Draft. The Duke product sparkled early and late, scoring 10 points in his first 5 1/2 minutes and finishing a strong debut impressively.

He wound up with 26 points and seven rebounds in 37 minutes. He was 10 of 16 from the floor but had eight of the 76ers’ 24 turnovers.

“Still just trying to get comfortable,” Okafor said. “It was my goal going into the game. My first NBA game, just trying to get comfortable. This is completely different than preseason. It seemed like a lot more intense, a lot of intensity, but trying to get comfortable as a team as well.”

Asked when it hit him he was in the NBA, Okafor said, “Right away, during the national anthem, that’s when I realized.”

Thomas keyed an onslaught by a deep Boston bench that outscored its four-man Philly counterparts 67-15. Forward Amir Johnson, making his Celtics debut, also came off the bench with 15 points and seven rebounds, and fellow reserve Jared Sullinger added 12 points and seven boards.

Among the starters, guard Marcus Smart led the way with 13 points and five assists.

“Our bench has to be a great source of energy and scoring and everything else for us,” Stevens said.

Forward David Lee, also making his Boston debut, chipped in with eight points, five rebounds and five assists. Forward Jae Crowder had 14 points and eight rebounds for the Celtics, who are opening with three straight games at home.

The Celtics, who led by as many as 20 points, had 31 assists on 39 baskets.

The Sixers, with only nine players available because of injuries, built a 26-17 lead in the first quarter, but the Celtics bridged the first and second quarters with a 21-2 run to take control of the game.

“It’s good to play through adversity,” Crowder said. “Winning’s not going to be perfect every time, and we weren’t expecting it to be. We knew they were going to come out with a lot of energy and high effort, so we fought through it and came out with a win.”

Forward Nerlens Noel, a local product playing in front of family and friends, had 14 points and 12 rebounds and guard Isaiah Canaan posted 18 points and seven assists for the Sixers.

NOTES: Boston F Kelly Olynyk missed the game serving a one-game suspension for his hit on Cleveland F Kevin Love during last season’s playoffs. G R.J. Hunter missed his Celtics debut because of illness. … G Isaiah Thomas became the first Boston player to come off the bench with 26 points or more in an opener since Reggie Lewis had 26 against Milwaukee in 1986. … C Jahlil Okafor became the first player to debut with 26 points or more since Gordan Giricek scored 29 for the Memphis Grizzlies in 2002. Before that. it was Lamarr Odom’s 30 for the Los Angeles Clippers in 1999. … G Nik Stauskas, who didn’t play in the preseason because of a right tibia stress reaction, was to make his 76ersdebut but missed the game with back spasms. … The Celtics observed a pregame moment of silence for Minnesota Timberwolves coach Flip Saunders, who passed away on Sunday.