BOSTON (AP) — Boston coach Brad Stevens talked before the game that he needed be flexible and rely on the team's depth when choosing a lineup.
The bench players seemed to be paying attention.
"Well our bench has to be a great source of energy, scoring for us and everything else for us," Stevens said after Boston's reserves outscored their counterparts, 67-15.
Coming off a 40-42 record and a seventh-place finish in the Eastern Conference in Stevens' second season, the Celtics entered their 70th year in the NBA loaded with a roster full of what could be described as complimentary players who could fill different roles.
It was Thomas that provided the spark after missing his first five shots from the floor.
"That's my job. I've got a job to do. I have confidence in myself and my teammates do, too," said Thomas, who finished 10 of 19 from the floor.
Philadelphia, meanwhile, is young again. Twelve of the 15 players on the 76ers' opening roster had two years or less of NBA experience. They went 18-64 last season, and then drafted Okafor out of Duke.
The undermanned 76ers relied mainly on seven players due to injuries.
"I knew that our offense was going to be poor," Philadelphia coach Brett Brown said. "We just haven't played together, so I ended up turning it into: Let's just post our bigs and sort of go (simple)."
Boston recovered from an early nine-point hole, triggered by a solid start from Okafor, who connected on his first five shots.
"That definitely got me in a good rhythm," he said.
The Celtics grabbed control in the final period, opening an 86-71 lead on Jonas Jerebko's transition 3-pointer from the left corner.
"Any time they cut it close, I thought we responded," Stevens said.
Philadelphia trailed by 11 at the break, but closed to 72-67 on Hollis Thompson's 3-pointer from the left corner. Boston then scored the final seven points of the third. Thomas, who had 13 in the quarter, nailed a 3 from the right wing in the final seconds.
Okafor had 10 points to help the 76ers open a 26-17 lead late in the first quarter before Boston scored 25 of the next 30 points.
Smart hit a 3 at the buzzer, giving Boston a 51-40 halftime edge.
Stevens had to change his defense, going to the bench early. He decided to double team Okafor after his solid start.
"I know Okafor is really good, but I thought we would mix that in later in the game," he said. "He played really well, got it going early in the game and forced us to make decisions."
Stevens said he encourages Thomas to keep going when he starts cold.
"A hot streak's coming,"' the coach explained. "Law of averages. Analytics."
76ers: Brown talked about how his team was dealing with injuries for the opener. "Going into tonight's game with nine and a half players," he said. "It's just part of the situation we've been dealt with." . G Tony Wroten (knee) and Kendall Marshall (knee) are both still sidelined after they each tore an ACL in January. C Joel Embiid will miss the season after the second surgery on his right foot.
Celtics: F Kelly Olynyk sat out his one-game suspension for his role in Cleveland F Kevin Love's left shoulder injury in last season's playoffs. . First-round draft pick R.J. Hunter was out sick and F/G James Young was inactive.
76ers: Host Utah in their home opener on Friday.
Celtics: Host Toronto on Friday.