Montreal Canadiens right wing Brendan Gallagher (11) vies for the puck with Vegas Golden Knights defenseman Alex Pietrangelo (7) during third period Game 1 NHL Stanley Cup semifinal playoff hockey action in Las Vegas, Monday, June 14, 2021. THE CANADIAN PRESS/AP-John Locher

LAS VEGAS - The uphill climb facing the Montreal Canadiens just got a little steeper.

The only Canadian team with a shot at the Stanley Cup gave up a 4-1 loss Monday in their first of a best-of-seven semifinal battle against the top-seeded Vegas Golden Knights.

It was Montreal's first game outside of Canada in 2021, and it came before a boisterous crowd of 17,884 — a far cry from what COVID-19 restrictions have allowed north of the border all season.

It was also against an imposing and powerful team, one the Habs haven't played all year, thanks to the one-time-only North Division — again, a product of the pandemic — that kept all their regular-season games against Canadian rivals.

"It's the situation that we're in this year — for everyone right now, at this stage, you're playing a team that you haven't played all year," said interim head coach Dominique Ducharme.

The Habs appeared to be keeping pace with the Knights throughout the first period Monday, but a sudden flurry of penalties in the second — including a fluke delay of game in the opening seconds — seemed to sap their strength.

"They have their strengths for sure, but we have ours also," Ducharme said. "I really liked the way we started, but the penalties really killed our momentum and our rhythm."

Shea Theodore opened the scoring with a fearsome one-timer that beat a sliding Montreal netminder Carey Price stick side 9:15 into the game.

It was the Vegas defenceman's first goal of the playoffs.

The Knights made it 2-0 early in the second when Theodore faked a shot then shovelled the puck over to Alec Martinez, whose faceoff-circle blast on a near-empty net left Price diving across the crease in vain.

Defencemen were responsible for 18 of the home side's shots on goal.

"They got some solid D-men over there," Price said after the game. "They were finding lanes and getting pucks through and jumping into the rush. That's what good (defenders) do, and we'll just have to find a way to mitigate that."

Price stopped 26-of-30 shots for the Canadiens, with one of his best of the night coming midway through the second when Max Pacioretty fed Mark Stone on a sudden two-on-one rush, only to be robbed by a spectacular glove save.

Marc-Andre Fleury turned in a 28-save performance for Vegas.

Montreal spoiled Fleury's shutout hopes with the man advantage at the 12:05 mark of the second frame when rookie Cole Caufield buried a juicy rebound off a Tyler Toffoli shot for his first goal of the playoffs.

But the momentum was short-lived: less than a minute later, Mattias Janmark made it 3-1 from the edge of the crease by tipping a drifting shot from Alex Tuch past Price's outstretched pad.

Knights defender Nick Holden made it 4-1 midway through the third and Reilly Smith registered his second assist of the night on the play.

Price headed to the bench shortly after Holden's goal, creating a four-minute stretch of six-on-five hockey that gave Fleury a chance to show off for the fans.

The series promises to be a chippy one — nearly every scoring rush during the first 20 minutes ended in a scrum behind or beside the net, frequently with frustrated Habs forward Brendan Gallagher at the centre of it.

Even so, the first frame produced only one power play per side — Montreal failed to capitalize on an early high-sticking call against Vegas centre Jonathan Marchesseault, then fought off the man advantage after Phillip Daneault hauled down Alex Pietrangelo deep in Montreal territory.

The penalty situation changed quickly in the second, which was only seven seconds old when Habs defender Ben Chiarot's blooper clearing attempt caught the netting above the glass behind Fleury, a delay-of-game call.

It seemed a turning point, triggering a series of penalties that the Canadiens never seemed to recover from.

"We liked our start, but after the penalties we were a little less dangerous, and not as good with the puck," Ducharme said. "That's something we will adjust — it's something we know we can do, and we know how to do it."

Montreal was 1-for-3 with the man advantage and Vegas went 0-for-4.

The top-ranked Golden Knights won an NHL-best 40 games in the shortened 56-game regular season and tied Colorado for the highest point total in the league — 23 points more than Montreal in the standings.

But the Canadiens have been the underdogs twice already this post-season.

They were not expected to beat the division-leading Toronto Maple Leafs in the opening round, nor were they favoured to overcome the third-place Winnipeg Jets in the second round. The team silenced critics in both cases and came into Vegas riding a seven-game win streak that included a sweep of the Jets.

It’s not all familiar territory for the Habs, though.

The Montreal-Vegas series is the first cross-border matchup in the NHL this season, made possible by a federal exemption allowing teams to bypass 14-day quarantine requirements.

Monday's capacity crowd was a stark contrast from the empty Canadian arenas during the regular season and even the 2,500 fans permitted inside Montreal’s Bell Centre during the playoffs.

This report by The Canadian Press was first published June 14, 2021.

News from © The Canadian Press, 2021