Sean Couturier gave the Flyers back the lead, 3-2, at 3:54 of the third period on the power play.
"I think we just refocused, came with a fresh mindset and battled hard," Couturier said. "We had, I think, better support throughout all three zones and created a few chances off of that."
James van Riemsdyk made it 4-2 on the power play at 9:37.
Pacioretty cut it to 4-3 at 18:15 with a 6-on-4 power-play goal.
The Flyers went 2-for-3 on the power play; the Golden Knights were 1-for-6.
"I think special teams was the difference in the game," Hart said. "Power play had two goals there, and PK we just shut them down all night. That was definitely the difference maker."
NOTES: Flyers captain Claude Giroux had an assist on Couturier's goal for his 334th power-play point (83 goals, 251 assists), surpassing Bobby Clarke for the most in Flyers history. … Yandle's assists came on the power-play goals, giving him 288 power-play points (38 goals, 250 assists), the most among active defensemen; San Jose Sharks defenseman Brent Burns is second with 262. … Flyers defenseman Kevin Connauton had one shot in 12:39 in his Philadelphia debut; he was claimed off waivers from the Florida Panthers on Tuesday. … Pacioretty's five-game goal streak ties the longest in Golden Knights history (Karlsson and Erik Haula, 2017-18). … Stone extended his point streak to seven games (three goals, seven assists).