MacKenzie Weegar had a goal and an assist, Dylan Guenther scored, and Clayton Keller had two assists for the Mammoth, who are the first wild card from the Western Conference. Karel Vejmelka made 29 saves.
Jack Eichel and Nic Dowd scored for the Golden Knights, who are the No. 1 seed from the Pacific Division. Carter Hart made eight saves.
Utah has won two in a row to lead the best-of-7 series 2-1. Game 4 will be here on Monday (TBD; Utah16, SCRIPPS, ESPN).
Weegar gave the Mammoth a 1-0 lead at 12:59 of the first period. Kailer Yamamoto couldn't connect on a pass with Liam O'Brien in the left circle, but Weegar skated into the loose puck in the high slot and scored with a slap shot that hit the mask of Hart before going in under his blocker arm.
Guenther made it 2-0 with a power-play goal at 17:45, roofing a one-timer under the crossbar from the top of the left circle.
Crouse pushed the lead to 3-0 at 4:07 of the second period, redirecting Nick Schmaltz's centering pass on a rush over the blocker of Hart.
Crouse scored his second goal of the period at 9:49, beating Hart again blocker side with a wrist shot from the high slot to make it 4-0.
Eichel made it 4-1 at 13:21, getting to a loose puck in the crease off a rebound and tapping it into an open net with his backhand.
Dowd cut it to 4-2 at 16:53 of the third period, beating Vejmelka blocker side from the low slot off a pass from Reilly Smith, who was below the goal line.
