LAS VEGAS – What happens in Vegas stays in Vegas.

Unless you do what the Flyers did Sunday night before a roaring sellout crowd at T-Mobile Arena.

They become one of the few visiting teams to defeat the first-year Vegas Golden Knights at home, getting three points from Sean Couturier and 38 saves from Michal Neuvirth as they left the Strip with a gritty 4-1 victory.

"Neuvy was the best player out there tonight," said captain Claude Giroux, whose team swept both ends of back-to-back games for the fourth time this season. "He made a lot of big saves and was able to shut them down. Without him, we don't win this game."

Vegas entered the night with an NHL-best 19-3-2 home record, and the Golden Knights outshot the Flyers, 39-18.

"They probably outplayed us most of the night," Couturier said after his fifth three-point game of the season. "Neuvy kept us in the game and we got a few lucky bounces to kind of get going a little bit. We found a way to win, and that's all that matters."

"We stuck to the game plan, to the system, and it turned out great for us," Giroux said.

About 3,000 fans wearing Flyers jerseys gave the sold-out arena a super-charged atmosphere. They watched the Flyers increase their winning streak to four games and remain one point behind second-place Pittsburgh in the Metropolitan Division. They inched to within five points of first-place Washington.

The Flyers, who played their first-ever game in Vegas, are 20-8-2 since their 10-game losing streak ended.

The top line of Couturier (goal, two assists), Giroux, (goal, assist), and Travis Konecny (two assists) again was dominant as they combined for two goals and five assists. The top line has 27 goals in the 21 games since  Konecny joined the unit.

Vegas dominated most of the second period and had a 14-2 shots advantage at one point in the session. But defenseman Andrew MacDonald and Giroux scored late in the period to give the Flyers a 3-1 lead.

With 2 minutes, 52 seconds left in the second, Couturier's shot from point-blank range deflected off MacDonald's skate and past Marc-Andre Fleury to put the Flyers ahead, 2-1. MacDonald had gambled and moved near the goal mouth on the play.

"I scissored down the wall when G (Giroux) was carrying it up," MacDonald said, "so I just tried to create some space for him. I went to the net because he was covered up high."

Giroux made it 3-1 with 5.8 seconds left in the second as he picked up a drop pass from the hustling Couturier and scored from the slot.

Radko Gudas' first goal of the season, an empty-netter with 2:26 remaining, locked up the victory.

Earlier, Couturier converted a right-circle feed from Konecny for his 28th goal, knotting the score at 1 with 2:10 to go in the opening period. The coming-of-age Konency later added another assist, giving him 20 points in his 21 games on the top unit.

Konecny has 29 points, one more than his rookie season in 2016-17.

The Flyers capitalized after Giroux intercepted a Vegas pass to put the goal in motion.

"We had a good cycle down low and we were able to keep the puck moving around and create some space," Couturier said. "We were aggressive at the blue line, and G made a nice play to keep it from going out."

Vegas took a 22-2 record into the night when scoring first, so the Flyers had long odds when defenseman Brayden McNabb blasted a shot past Neuvirth from just above the left circle, giving the speedy Golden Knights a 1-0 lead with 8:38 left in the first.

The Flyers were coming off a grueling 4-3 shootout win in Arizona on Saturday night. The Golden Knights were well-rested, having played their last game on Thursday.

"Playing back-to-back, we're not going to use it as an excuse," MacDonald said before the game. "We're prepared and excited to get out there as usual."

There were numerous "Let's Go Flyers!" and "E-A-G-L-E-S" chants throughout the night as the visitors handed Vegas its second straight home loss for the first time in its young history.

"Great crowd. It was so much fun to play in front of a crowd like that," said Neuvirth, who figures to get more playing time until Brian Elliott returns from an injury. "On the way to the rink from the hotel, I saw so many fans in our jerseys. It was nice to see."