TORONTO — As the Raptors prepared to inbound the ball from the sideline early in the third quarter against the Celtics on Monday night, Jayson Tatum took a few steps away from the action and began clapping his hands with some vigor.
He wasn’t celebrating some big play or big run. The Celtics still trailed, and they were not far removed from their lethargic first half.
But Tatum sensed that the game’s tenor was beginning to shift. Suddenly, the Celtics were reaching the loose balls first. They were the ones putting pressure on by attacking the rim.
And perhaps most importantly, they were the ones who had already built an extensive portfolio of wins that made them realize that sleepy starts could be undone.
Advertisement
“We do a great job of not panicking,” Tatum said, “and we do a great job of responding more often than not.”
In this case, the Celtics pushed aside their uneven first half and pummeled the Raptors by 17 points in the third quarter, eventually seizing a 116-110 win that made Boston the NBA’s first 20-win team.
“We’ve been the best team in the league for a minute,” guard Marcus Smart said, “and every night throws a different challenge at us.”
In this case, there were several. The Celtics were playing in their second road game in as many nights, against a well-rested opponent. Center Al Horford was sidelined to rest his back and sixth-man Malcolm Brogdon was ruled out because of an illness.
The Raptors, who have been slowed by injuries, were mostly whole. And the Celtics’ perch atop the NBA meant that this game did not really ignite any urgency. In other words, it would have been understandable to have a dud.
But after a first half in which turnover issues resurfaced and Tatum was slowed down by Toronto’s trapping defense, coach Joe Mazzulla looked at the scoreboard and saw that his team trailed just 62-56.
Advertisement
“I said, ‘We’re down 6, it’s a two-possession game, we haven’t played the way we wanted to,’” Mazzulla said. “Let’s just be patient. It’s the second night of a back-to-back, just continue to do what you do.’”
The Celtics trailed, 64-56, early in the third quarter before Tatum and Marcus Smart (18 points, 7 assists) ignited the run. In the period the two combined for 25 points, 6 rebounds, and 4 assists, sparking the 35-18 burst that gave the Celtics a 91-80 lead.
Boston led by as many as 13 points in the fourth before the Raptors put together a mild rally, pulling within 113-108 on a Pascal Siakam free throw with 1:19 left. The Raptors then came up with a steal, but a pass to OG Anunoby in the right corner slid right through his hands and out of bounds. At the other end, Blake Griffin, who had a strong game starting for Horford, tipped in a Tatum miss.
“It was great to see us not panic,” Griffin said. “I think that’s a very big thing.”
Tatum scored 17 points in that explosive third quarter and finished with 31 points and 12 rebounds. Jaylen Brown added 22 points, and Griffin had 13 points and 8 rebounds. After committing nine turnovers in the first half, several on unforced miscues, Boston had just two in the second.
“We’ll have ebbs and flows throughout the year,” Mazzulla said. “I feel like we got in a great rhythm, and then you’re going to constantly have to reinvent yourself as a team and it’s not always going to go your way. So it’s more about how can we maintain an awareness of that and work through it and execute it?”
Advertisement
Pascal Siakam had 29 points, 8 rebounds, and 7 assists to lead the Raptors (12-12), yet another Eastern Conference team that started this year with grand expectations but is now treading water around the .500 mark as the season surges past the quarter pole.
Before the game, Toronto coach Nick Nurse talked about his admiration for how Celtics president of basketball Brad Stevens has solidified his roster around Tatum and Brown, with special mention for the additions of Brogdon and Derrick White.
“And somebody traded them Horford back,” he said with some exasperation, referring to the big man’s return last year following a lost season with the Thunder.
This team’s depth has been on full display, and Monday was no different. Griffin has rarely been part of the rotation, but he once again stepped into a significant role when he was needed.
The 33-year-old even threw down another big one-handed dunk, and later said he’d like to do that once a game so people stop acting as if it’s some miracle.
“I always want to be out there,” Griffin said, “but we have the luxury of having so many great players, and guys on the bench who could be playing a lot of minutes for other teams. But, sometimes you sacrifice to be on a team like this.”
Advertisement
Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him @adamhimmelsbach.