LAS VEGAS — Nic Dowd redirected Noah Hanifin’s shot from the point to put Vegas ahead at 7:20 of the third period and the Golden Knights beat the Utah Mammoth 4-2 on Sunday night in Game 1 of their first-round series.“I didn’t do a lot, to be honest,” Dowd said. “It’s probably better if it gets on and off my stick that quick. … I just found a little bit of space. Everywhere across the league, there’s limited space out there. Guys are playing their best hockey defensively because everything matters that much more. It was a bang-bang play.”Game 2 is Tuesday night in Las Vegas.The Golden Knights, who twice trailed before scoring three third-period goals, have not lost in regulation since John Tortorella (8-0-1) took over as coach.The Mammoth lost in the franchise’s first playoff game since 2020. They are in their second season in Utah after leaving Arizona.“It was a hard-fought game,” Mammoth coach Andre Tourigny said. “It was physical. It was intense. Every inch was contested.”Colton Sissons had a goal and assist for the Golden Knights and Mark Stone and Ivan Barbashev also scored. Carter Hart stopped 32 shots. Hanifin had two assists.Logan Cooley and Kevin Stenlund scored for the Mammoth. Karel Vejmelka, playing in his first playoff game after five years in the Utah/Arizona organization, made 27 saves. Captain Clayton Keller, who closed the regular season with 16 assists over a 10-game streak, failed to record one in this game.The Golden Knights took the fight to the Mammoth from the beginning and f …