Michael Raffl had a goal and two assists, and Travis Konecny and Oskar Lindblom each had a goal and an assist for Philadelphia (3-3-1), which had been 0-3-1 in four games following a 2-0-0 start. Kevin Hayes, Ivan Provorov and Matt Niskanen also scored. Brian Elliott made 33 saves.
The Flyers had scored seven goals during their losing streak, and their 15 goals entering play Monday were the fewest in the NHL.
"We're confident in how we want to play, and we strongly believe that if we play the way like we played the last three games we're going to be successful," Flyers forward Claude Giroux said. "Just because it's not going in you can't start changing everything, how you're playing. We felt strongly that if we play our game, we're going to give ourselves a chance to win every night."
WATCH: [All Golden Knights vs. Flyers highlights]
Jonathan Marchessault and Reilly Smith scored for Vegas (6-4-0). Oscar Dansk, in his first game of the season, made 31 saves.
"I thought some guys on the team competed real hard and I thought some guys were real loose in the [defensive] zone and we gave them too many good scoring chances," Golden Knights coach Gerard Gallant said.
Konecny gave the Flyers a 1-0 lead with a power-play goal at 4:15 of the first period. Lindblom tried centering a puck to Shayne Gostisbehere but it bounced off the stick of Golden Knights defenseman Jon Merrill and went to Konecny, who beat Dansk high over his glove.
Hayes started the goal rush in the second period, scoring from the post to Dansk's right at 6:12 to make it 2-0, and Provorov made it 3-0 at 6:56 with a shot from the left point that got through traffic.