LAS VEGAS >> Back in the Stanley Cup Final for the first time in five years and trailing the Florida Panthers less than 10 minutes into Game 1, the Vegas Golden Knights sent a very clear message.

“We were ready,” Jonathan Marchessault said.

Ready and dominant. Vegas rallied from an early deficit, got the go-ahead goal from Zach Whitecloud with just over 13 minutes left and arguably the best save of the playoffs from Adin Hill and beat Florida 5-2 Saturday night to take the lead in the best-of-7 series.

“We kept our composure, and it was good,” said Marchessault, one of six original Knights players left from the start of the franchise in 2017 who scored the tying goal in the first period. “We just wanted to play the right way and be disciplined, and tonight we were able to be the better team.”

Whitecloud put Vegas ahead, a crucial penalty kill followed and captain Mark Stone scored an insurance goal that was reviewed for a high stick and confirmed. Reilly Smith sealed it with an empty-netter to make the score look more lopsided than the game.

The combination of that offense and Hill’s 33 saves put Vegas up after a feisty opener between Sun Belt teams who wasted little time getting acquainted with big hits during play and plenty of post-whistle pushing and shoving.

“It’s exactly what we expected,” said Vegas defenseman Shea Theodore, who scored his first goal of the playoffs and ended a 27-game drought dating to March 7. “That’s how they wanted to play. We were just trying not to play into it.”

That stuff is just beginning. Game 2 is Monday in Las Vegas.

Before the Panthers even get a chance to respond, they ratcheted up the physical play late after falling behind by two. A handful of penalties resulting from a fracas with 4:24 remaining left the Florida bench well short.

The outcome was determined long before that.

After falling behind on a short-handed goal by Eric Staal that sucked the life out of the crowd of 18,432, the Golden Knights rallied for their ninth comeback win this playoffs. Marchessault — known since arriving in Las Vegas for scoring big goals — answered before the end of the first period.

Early in the second, Hill made a desperation stick save to rob Nick Cousins of what would have been a sure goal. The save was reminiscent of the one Washington’s Braden Holtby made against Vegas — in the same crease — five years ago.

“That’s an unreal save — it’s a game-changer,” coach Bruce Cassidy said. “You need those saves at key moments.”

Giving up a tying goal to Anthony Duclair with 10.2 seconds left in the second did not slow the Golden Knights’ momentum much. Whitecloud’s goal, with two-time Vezina Trophy-winning goaltender Sergei Bobrovsky screened and unable to see, fired up fans once again.

Bobrovsky, in the final for the first time, downplayed any reason for concern after stopping 29 of 34 shots and losing for just the second time in 12 games this postseason.

“I played a good game,” Bobrovsky said. “I played a solid game. They created some good chances other than goals. They had lots of good scoring chances, and that was fun.”