LAS VEGAS — Improving their defensive play on the road is one of the Flyers’ New Year’s resolutions, and their first game in 2020 was not a good start to fulfilling that goal.

Despite a valiant comeback effort, their well-documented road woes continued as they fell to Vegas, 5-4, Thursday at ear-splitting T-Mobile Arena.

The Golden Knights killed off a late six-on-three Flyers power play to seal the win.

Max Pacioretty scored a pair of goals to pace Vegas, which has won three straight on its season-high seven-game homestand.

“We didn’t play well in the first half of the game, but I thought the second half was great,” said defenseman Ivan Provorov, whose team fell behind, 4-2, in the opening period. “But it was too late.”

Vegas used its speed and its forechecking to trigger its offense and set up repeated scoring chances from behind the net.

“They’re a fast team and come hard,” said losing goalie Carter Hart after making 10 third-period saves to help the Flyers stay within striking distance. “They don’t play a lot of defense and kind of like to transition a lot. Kind of a slow start , but after the first period I thought we kind of gathered things together and got back to our game.”

The Flyers reached the halfway point of their schedule — 41 games —with a 22-14-5 record and 49 points. They were 15-20-6 for 36 points at a corresponding point last season.

The Flyers are 1-3 on their season-high, six-game road trip, which resumes Saturday in Arizona and ends Tuesday in Carolina. They have been outscored, 16-8, in those three losses.

The Golden Knights took a 5-2 lead midway through the second when Cody Glass, despite being tightly covered by Scott Laughton, shook free for a split second and fired a slot shot past a screened Hart.

“There’s a couple I want back, but in the second and third (periods), I felt a lot better,” Hart said.

Sean Couturier answered with 7:52 to go in the second, scoring on a rebound to slice the deficit to 5-3.

Couturier wasn’t finished.

Fifteen seconds into the third period, he scored on a one-timer from the left circle while the Flyers were on a power play. That got the Flyers within 5-4 and gave Couturier three points on the night.

The Flyers got a power play on a delay-of-game penalty on Vegas with 2:46 left in regulation. They pulled Hart (28 saves) with 1:54 remaining to get a six-on-four, and then drew another penalty to have a six-on-three for 43 seconds.

Vegas had a couple of blocked shots and four late clears --one on the six-on-three, three on the six-on-four -- to preserve the win.

“Those are the opportunities you have to take advantage of,” said Provorov, who had a pair of assists and five shots in the defeat.

“You win games with the power play, and we’re not doing that enough,” said Couturier after collecting two goals, an assist, and winning 65 percent of his faceoffs.

In a wildly entertaining first period that had a little bit of everything except defense, the Flyers fell into a 4-2 hole. It marked the second straight game they had surrendered four first-period goals.

The Flyers got the start they wanted as Claude Giroux (two points, eight shots) converted a perfect feed from Jake Voracek and scored his team-leading 13th goal, giving the Flyers a 1-0 lead with 12:27 left in the first.

But Vegas scored three goals in a 2:45 span to go ahead, 3-1. Shea Theodore (right circle), Pacioretty (power-play rebound), and an uncovered Jon Merrill (rebound) scored the goals.

Merrill, 27, a defenseman his entire career, was playing left wing for the first time ever. He scored his first goal in 52 games dating back to February.

Shortly after Laughton was denied by Marc-Andre Fleury (34 saves) on a penalty shot, the Flyers made it 3-2 on a sensational goal by Travis Konecny, the team’s lone All-Star selection. Konecny went around defenseman Nate Schmidt and beat Fleury with a backhand-to-forehand move with 5:20 left in the first. It was his first goal in eight games since returning from a concussion.

Mark Stone sent Pacioretty in alone after Misha Vorobyev (minus-2) got burnt, and the left winger beat Hart for his second goal of the night, putting the Knights ahead, 4-2 with 2:57 to go in a first period in which the teams combined for 30 shots and six goals.

Hart, hung out to dry on several occasions by his defensemen and forwards, allowed more first-period goals (four in 20 minutes) than in his last three home games combined (three goals in 180 minutes).

Hart is 2-8-1 on the road and 11-1-2 at home.

The Flyers have been Team Enigma: Stingy at the Wells Fargo Center, unable to contain teams on the road. They began the night allowing just 1.95 goals per game at home (best in the NHL), but 3.62 goals per game on the road (27th in the NHL).

They vowed to play a tighter defensive game on Thursday, but Vegas wouldn’t allow that to happen.

Breakaways

The Flyers are now 13-2-1 when Couturier has three points or more. ... The Flyers outshot the Knights, 38-33. ... Theodore, a defenseman, had eight shots for the Knights. ... Chris Stewart had six hits in 6:12 but did not play in the third period as Alain Vigneault shortened his bench. Vorobyev played just 44 seconds in the third.