MONTREAL — The Celtics closed the preseason with a 137-134 overtime loss against the Raptors on Friday night, but it hardly felt like an exhibition.
Coach Joe Mazzulla leaned on his regular rotation players for most of the night, even sending Jaylen Brown and Al Horford back into the game midway through the fourth quarter. All-Star forward Jayson Tatum might have joined them, but he was ejected late in the third quarter after collecting his second technical foul.
That was part of a bizarre sequence in which the Celtics collected three technicals in short order. Grant Williams stepped in to defend Tatum and said he told the official, “Referee the game, not your emotions.” Moments later, Boston received a delay-of-game technical when Tatum did not leave the floor in a timely manner.
This game, part of the NBA’s “Canada Series,” had a lively atmosphere and a competitive feel, with the majority of this sellout crowd standing and roaring during the chaotic final moments of regulation — a time in preseason games when empty seats tend to outnumber occupied ones.
The night’s buzz was dented only by the condensation seeping through the hardwood in this hockey rink, causing some slippage and brief delays. Marcus Smart said he tweaked his groin when he took a particularly hard fall late in the fourth, and he was not pleased with the playing conditions.
“A player’s safety has to come to the focus at some point,” he said. “Six, seven guys fall in the same spot, that’s a problem.”
Brown and Derrick White had 23 points apiece to lead the Celtics. Tatum finished with 21. Malcolm Brogdon sat out the second half due to a sore right leg, but Mazzulla said it was just precautionary.
The Celtics, who will have to experiment with small lineups while center Robert Williams is sidelined following knee surgery, surrendered 22 offensive rebounds.
“Everybody 1-5 is going to have to put a body on your man, and if you don’t get it, make sure your man don’t get it,” Smart said. “We’ve just got to help each other. We can’t leak out. Our guards have to go get long ones. We can get out and run once we do that.”
Justin Jackson, who is vying for one of the final roster spots, gave the Celtics a 127-126 lead on a runner with 36.8 seconds left in regulation. After Josh Jackson tied the score by making one of two free throws for Toronto, Celtics guard Payton Pritchard had a chance to win the game, but missed a jumper at the buzzer.
The Raptors started the extra session with a 7-0 run and appeared in control before the Celtics got a final chance, trailing, 137-134, with 7.7 seconds remaining. Pritchard slipped free for a clean look, but it caromed off the rim.
“I thought there were a lot of good lessons for us to learn, players and coaches,” Mazzulla said. “And I thought that was exactly what we needed to go through heading into the season.”
The Celtics open the regular season Tuesday at home against the 76ers.
Observations from the game:
⋅ Mazzulla said he wanted to essentially treat this as a regular-season game, and he stuck to that with a nine-man rotation deep into the third quarter. (Pritchard remained on the bench.)
Smart said it was important for the regulars to ramp up their conditioning after most of them sat out last Friday’s preseason game against the Hornets.
“It felt good for us to just get back in the rhythm,” he said.
White started again and appears positioned to start opening night. Still, there were some opportunities for Mazzulla to experiment with unusual groups. During one second-quarter stretch, the lineup consisted of Brown, Brogdon, Smart, Williams, and Sam Hauser. Smart guarded the center. These units will have little trouble scoring, but they’ll be vulnerable at the other end and on the glass. In this case, the Raptors quickly found success inside.
“I think it’s great that happened tonight, so we can fix it,” Mazzulla said of the rebounding issues.
⋅ Late in the second quarter, Tatum spent about a minute showing a court attendant where to sop up some condensation. Then play resumed and the floor was still slippery, and Williams and Horford both pointed it out before play was stopped. Late in the fourth quarter Smart took a hard spill on another wet spot at the other end of the floor. He thought the officials should have done a better job of halting the game to ensure that the wet spots had been treated.
“That could’ve been scary,” said Smart, who said he doesn’t expect his sore groin to sideline him Tuesday.
⋅ White has been working extensively on his jump shot after practices this month. He is not looking to alter much mechanically, but he is trying to be more prepared to shoot the instant there is an opportunity. He had good results in the first quarter, when he mostly camped out in the right corner and drilled four in a row. Two came on drive-and-kicks by Tatum and Brown, who will draw plenty of attention in those situations this season.
⋅ Williams was pushing toward the hoop on a second-quarter fast break when he took an awkward step and his right foot exploded out of his sneaker. He was fortunate he didn’t injure himself on the play, but his teammates got a kick out of the equipment malfunction.
Williams was given a new shoe during the ensuing timeout, and he promptly drilled a 3-pointer.
⋅ Blake Griffin is still learning the Celtics’ system, and there are occasional reminders. On one second-quarter play, a short pass from Brogdon bounced off Griffin’s back. The two chatted about the mix-up right away, with Brogdon pointing out where Griffin should have been. Griffin had some nice moments in the paint in the second half, though.
⋅ Celtics legend Robert Parish attended Friday’s game. He received a warm ovation when he was introduced.
Adam Himmelsbach can be reached at email@example.com. Follow him on Twitter @adamhimmelsbach.