Lowry scored 35 points and had a key steal in the closing minute to lead the Raptors to a 110-107 win over the Boston Celtics on Wednesday night.
With big men Amir Johnson and Jonas Valanciunas sidelined, Lowry took over for the Raptors in the second quarter and carried them from there.
"He came out aggressive," forward DeMar DeRozan said. "We need him to do that."
DeRozan had 23 points and Patrick Patterson added 14 for Toronto, but it was Lowry that Boston coach Brad Stevens praised.
"I said before the game that he probably should have been an All-Star last year," Stevens said. "It looks like he took that one seriously because he looked like one tonight."
It came after the Raptors fell behind by 16 points in the first quarter.
"We can't be that way," coach Dwane Casey said. "It shouldn't have to come from me to crack the whip at every turn to get us going."
Rajon Rondo led Boston with a triple-double of 13 points, 15 assists and 10 rebounds. Jeff Green had 20 points for the Celtics, who have lost three straight after a season-opening win over Brooklyn.
"They were missing some guys and he knew he needed to step up, and did his job," Boston forward Kelly Olynyk said of Lowry.
With the score tied at 105, Lowry stripped rookie Marcus Smart and fed DeRozan for a fast-break layup with 33 seconds left. He was fouled on the play and hit the free throw.
"If he got by me he would have got a layup," Lowry said. "I knew DeMar's always going to trail me. I was just hoping he was hurrying up."
Rondo's two free throws sliced it to one, but Lowry nailed a fadeaway jumper from the left wing with 8 seconds to play.
Green back-rimmed a long 3 and Boston's Jared Sullinger grabbed the rebound, but time ran out.
Boston had overcome a horrible shooting stretch filled with turnovers, rallying to tie it at 105 on Smart's 3-pointer from the top with 1:10 to play.
The Celtics trailed 102-97 with 2 1/2 minutes left.
Toronto trailed by seven, but closed the third quarter with an 11-2 spree, taking its first lead since the game's opening basket on a driving floater at the buzzer by Lou Williams.
Leading 88-86 after three, the Raptors pushed it to 92-86 on James Johnson's steal and breakaway jam with just over nine minutes left. The Celtics went 5 1/2 minutes without a basket.
After Sullinger's three-point play — Boston's only basket in a 10 1/2 minute stretch — cut it to 94-92, the Raptors scored the next six points. The Celtics had already committed 27 turnovers midway into the final quarter and finished with 28.
Lowry scored 14 points in the third quarter, taking over by handling the ball for long stretches before either driving to the middle of Boston's defence or hitting long jumpers.
The Celtics had opened a 27-11 lead eight minutes into the game, but the Raptors — sparked by Lowry's nine points — got back in it with a 15-0 run over a 3 1/2 minute stretch late in the second quarter and closed it to 57-54 at halftime.
Raptors: C Valanciunas did not play after leaving Tuesday's win over Oklahoma City with a bruise on his right hand at the start of the second quarter. He returned to that game, but left again after getting accidentally hit in the face. "There's nothing broke, everything's negative," Casey said before the game. "A little bit of everything. He got beat up pretty good, got hit in the nose, and cracked his knuckle on somebody's knee or something." ... F Johnson (sore left ankle) missed his third straight, but Casey said he expects him to return Friday.
Celtics: C Vitor Faverani, who had off-season knee surgery in Europe, was back with the team. "There's a long way to go before he gets back on the court," Stevens said.
WHAT A NIGHT
Lowry was 12 of 17 from the floor, nailing two from beyond the 3-point line. He also was 9 of 10 from the free throw line, had four assists and four rebounds in 35 1/2 minutes. "He's just really good," Stevens said.
The Celtics hit 15 of 19 shots in the opening quarter en route to a 35-23 lead after one.
Raptors: Host Washington on Friday.
Celtics: Host Indiana Friday.