Mitch Marner didn’t join the Vegas Golden Knights to win one round in the playoffs. Or two — or even three — for that matter. It’s a good start, though. Marner left his fingerprints at different times throughout the Knights’ six-game series win over the Utah Mammoth in the first round. Little plays here, assists there, all to the tune of seven points in six games. He saved his best effort for last Friday at Delta Center with two goals and an assist to pace the Knights in the 5-1 win , including the game-winning goal off a near-three-minute shift . “It was his best game of the series,” coach John Tortorella said. “He just looked comfortable.” This is the kind of game the Knights were hoping for when they landed Marner in the eight-year, $96 million sign-and-trade with the Toronto Maple Leafs on July 1. With Marner came the perception that he wasn’t a big-time playoff performer. How he hadn’t scored a goal in Games 5-7 of a playoff series since 2019 prior to Friday.…