LAS VEGAS — The wait is over.

Mitch Marner finally debuted for the Vegas Golden Knights Thursday in the team’s third preseason game. The 29-year-old forward, which Vegas acquired from the Toronto Maple Leafs for Nic Roy and gave him an eight-year, $96 million deal skated with Jack Eichel and Ivan Barbashev in Vegas’ 3-2 overtime win over the Utah Mammoth at T-Mobile Arena.

Shea Theodore produced the game-winner after losing his stick, picking it up, getting the puck and scoring on a backhand off a breakaway as the Knights cracked the win column for the first time this preseason.

And while everyone was curious about Marner, it was also the preseason debut for Eichel and Barbashev. And while everyone expects this line to be together the entire season and be highly productive, things happen. Injuries. Slumps. Matchups. Any of which could necessitate coach Bruce Cassidy changing things.

But Thursday was a taste of what we might expect from what will be Vegas’ top line.

Marner was greeted with cheers from the crowd of 17,383 as he hopped over the boards for his first shift. He got off a shot but it was wide of Utah goalie Vitek Vanecek.  

And if you thought Marner’s and Eichel’s presence would mean more offense, guess again. At least early on. 

The Knights had just three first-period shots. Utah, meanwhile, didn’t get off its first shot until less than five minutes remained in the opening stanza. The difference is, that shot went in as Dylan Guenther beat Adin Hill.

Guenther scored again 1:06 into the second period. Normally, this would be a bad sign as Vegas found itself chasing the game. But Thursday, it was more about seeing how these lines that Cassidy rolled out performed together.

Eichel and Marner had a nice give-and-go below the Utah goal line and while it didn’t generate a scoring chance, the play itself was indicative of the hockey IQ these two possess. Barbashev had a great opportunity early in the game at the doorstep but couldn’t finish, something that has plagued him at times during his tenure with the Knights.

But midway through the third period, what the announced crowd of 17,383 came to see, happened. The Mammoth turned it over deep in its zone, Marner collected the loose puck, found Eichel cruising the slot and his shot eluded Vanecek to cut the deficit to 2-1.

I guess that’s what Marner Magic is all about.

 “They made some plays,” Cassidy said of Marner and Eichel working together. “They were trying to look for each other and still play their game. You could see pockets of what they can do together. They’re just out of sync. It was their first game action.

“I thought as the game wore on, they got more touches and seemed more comfortable. They’re the reason we won the game.”

Eichel then tied it as Barbashev fed him in the high slot and his shot from the top of the circle beat Vanecek. It led to overtime and Theodore’s heroics.

Barbashev, who had two assists, said he will learn how best to play alongside two skilled players as Marner and Eichel.

“I thought there was a little more understanding in the third period of where to be,” Barbashev said. “It’s a lot of fun playing with both of them.”

Barbashev said he’ll need to adjust his vision on the ice to be on the same page as Eichel and Marner.

“It’s a different mentality,” he said. “I think it’s just a matter of learning where to be and be ready.”

Theodore said having Marner on the ice , especially as part of the first power play unit, can change the dynamic of how to attack with the man advantage.

“I thought it was a tough adjustment early, but as the game went on, things cleaned up,” he said. “Obviously, we’re working through some things but that’s what the preseason is for.

“I remember playing against (Marner) in Toronto. He’s an exceptional playmaker and has a really good stick. Him and Jack shooting the puck, it’s a pretty good combo.”