TORONTO -- Celtics coach Doc Rivers called his team's play "awful" after Thursday's overtime loss to the Lakers. Friday's loss at Toronto kept his mood dismal.
"I was really frustrated with our execution," Rivers said. "We couldn't even run a play out of a timeout. That's just frustrating. That's focus or something. We have to fix that, because we've been playing too well for this to go back down that road again.
"We'd kind of worked out all our kinks and then, all of a sudden the last couple of games, it's returned out of nowhere."
Rivers, who lambasted his players during one first quarter timeout, huddled with his staff outside the locker room for several minutes after the game.
Asked whether Sunday's home game against league-leading Chicago could be the tonic to get his team back on track, Rivers didn't think so.
"The way we played the last two games, we need to be in a gym running," Rivers said.
The Celtics scored 75 or fewer points for just the third time in franchise history and the first time since Jan. 12, 2001, when they had 72.
Amir Johnson had 12 points and 12 rebounds and Aaron Gray matched a season high with 11 rebounds as the Raptors avenged a 100-64 loss at Boston on Feb. 1, their worst defeat of the season. James Johnson scored 14 for Toronto.
"We knew they had a back-to-back with the Lakers," Amir Johnson said. "Our strategy was just to come in and hit them in the mouth."
The Raptors, who snapped a three-game losing streak, had lost five of six coming in. They were treated to a rare standing ovation from the crowd of 19,207 in the final minute.
"I don't even remember the last time we beat Boston," Calderon said. "They're always beating on us."
"You can't take anything positive away from this game," Rondo said. "You've just got to move on."
The Celtics, who had won nine of ten before Thursday's defeat, dropped back-to-back games for the first time since a five-game skid from Jan. 6-16.
"We just didn't show the mental toughness tonight," Pierce said. "We feel like we're getting so close to being the team we want to be and the to take a couple of steps back is definitely frustrating. These are games we're supposed to win."
Trailing 63-51, to begin the fourth, the Celtics were unable to mount a serious comeback. Allen's jumper cut it to 77-69 with 3:35 left, but Linas Kleiza answered with a 3-pointer. And after Garnett made one of two from the line to trim the deficit to 81-72 with two minutes left, Calderon hit a step-back 3 to push the lead back to 12.
"By the time the fourth quarter came they made shots and we couldn't stop them," Allen said.
Toronto started strong, using a pair of running dunks by James Johnson and Calderon's alley-oop pass to DeRozan to open an 18-7 lead with 4:30 left in the opening quarter. DeRozan had nine points in the first, Calderon and Johnson had eight each as Toronto led 26-14 after one.
Boston made six turnovers in the first, but also had Rivers fuming after failing to inbound the ball on one possession, forcing a timeout. Rivers yelled angrily at his team in the huddle before stomping back to the bench to let the players sort themselves out.
"In a way, (Thursday) night's loss kind of lingered on to this loss today," Rondo said. "It's a different story if we won."
The Celtics closed the gap in the second, when Toronto made just four of 15 field goal attempts, but still trailed 41-34 at the break. Allen and Rondo combined for only two points in the first half, missing seven of eight shots.
The Raptors pulled away again in the third with DeRozan feeding Amir Johnson for an alley-oop to make it 61-45 with 3:52 left, matching their biggest lead of the game. Boston trailed 63-51 heading into the fourth.
DeRozan has scored 20 or more in three of his past four games. ... The loss snapped Boston's season-high three-game road winning streak. ... Celtics G Avery Bradley (right shoulder) and F Sasha Pavlovic (left wrist) sat out for the second straight game. ... The Raptors are 7-2 this season when leading at the half. ... Toronto G Jerryd Bayless was unavailable after leaving Wednesday's loss to Milwaukee with a sore left ankle.
Former pro players Jason Collins and Sue Wick, along with NBA commissioner Adam Silver and WNBA president Lisa Borders, served as representatives on the leagues' parade float.
Miami Heat center Hassan Whiteside says he wants to know who his next team is on Friday, the first day of this summer's NBA free-agent period.
The Wizards think it is unlikely that Kevin Durant will sign with them in free agency, according to a team source who told ESPN's Britt McHenry that "it's not like LeBron and Cleveland."