Jakub Voracek (19th) returned from a two-game National Hockey League suspension to open the scoring on a scorcher right off a faceoff win by Nolan Patrick.
Kasperi Kapanen will not play for the Toronto Maple Leafs when they host the Chicago Blackhawks at Scotiabank Arena on Wednesday (7 p.m. ET; NBCSN, SN, TVAS, NHL.TV) because of a concussion.
Brandon Saad had a goal and an assist, and Duncan Keith, Dominik Kahun and Alex DeBrincat also scored as Chicago jumped out to a 5-0 lead before holding on for the win. Chicago (31-30-9) moved within four points of a wild-card berth in the Western Conference.
"We can be really happy with the first and second and be not happy with the third [period]", Chicago coach Jeremy Colliton said.
Corey Crawford saved 17 of the 18 shots he faced in the Chicago goal but left because of illness after the second period. Colin Delia had 26 saves - all in the third.
"We've got to learn from the third period because that was way too close", Hawks forward Marcus Kruger said.
The Flyers went 0-for-2 on the power play, including one late in the second period and early into the third period that set a bad tone for the rest of the game. Garret Sparks replaced Frederik Andersen in the Toronto goal at the start of the second period after the Blackhawks scored four first-period goals.
"I just think as we go here, we're getting more comfortable with how we have to play to win", said Colliton, who replaced the fired Joel Quenneville on November 6 with the Hawks 6-6-3. "And we're doing it more and more consistently which is nice to see and it's got to continue".
Perlini notched his 12th goal this season, and seventh in his past six games, beating a Maple Leaf before firing a wrist shot from the high slot at 12:55 of the first period.
Toronto, which beat Chicago at the United Center in a wild 7-6 overtime affair back in October, finally got on the board with 1:33 left in the period when Rielly had his shot deflected in by Johnsson for his 20th. With five minutes left in regulation, Auston Matthews put the Leafs ahead to stay, and 2:21 later, scored again (33rd and 34th) to put a stranglehold on the game. The Philadelphia Flyers are averaging three goals per game and are scoring on 17.1 percent of their power play opportunities.
"We didn't put ourselves in a very good position", Rielly said. "The playoffs have already started, if you ask me".
The 22-year-old native of Finland was listed as being out for precautionary reasons due to illness on Monday night against the Tampa Bay Lightning.
Defencemen Jake Gardiner (back) and Travis Dermott (shoulder) remain out.
NOTES: Chicago is 14-3-2 in its last 19 games against the Leafs ...
The Maple Leafs put 29 shots on net in that final 20 minutes, leaving them one shot shy of being the eighth National Hockey League team to ever put 30+ shots on goal in a single period. However, officials on the ice in Toronto ruled that Delia knocked the net off accidentally, denying the Leafs of a clean opportunity at a game-tying goal.