Matvei Michkov and Sean Couturier each scored for Philadelphia (29-23-11), which had won four of its previous five games. Dan Vladar allowed six goals on 24 shots before being removed after two periods. Samuel Ersson stopped all three shots he faced in the third period.
"I think mentally we weren't sharp," Couturier said. "We gave up a lot of quality chances and they capitalized on us."
The Rangers' top line of Zibanejad, Perreault and Lafreniere created several of those chances. They combined for seven points (four goals, three assists) in their fourth game together.
"I think there's complementary skill sets in the sense that they're a little bit different in what they bring, although I think the common denominator is they all have pretty good offensive instincts," Sullivan said. "Mika is a real cerebral player, and he plays on both sides of the puck so he's very conscientious. ... Mika and 'Laf' are strong on pucks in the offensive zone, their ability to protect pucks and hang on to pucks, and I think Gabe is getting better in that regard."
Perreault displayed his physicality and play-making ability Monday.
His strong forecheck on Flyers defenseman Jamie Drysdale created a turnover behind the Philadelphia net, which led to Zibanejad's goal at 13:07 of the first period that gave New York a 2-0 lead.
Then the 20-year-old rookie made a blind backhand pass through the crease to set up Zibanejad's power-play goal that made it 5-1 at 18:40 of the second period.
"The skill and stuff, it's been pretty evident for everyone," Zibanejad said. "But just the way he sees the ice, the way he makes plays. The power-play goal is a perfect example of the way he makes a play. ... The more he plays, the more confident he gets."