Guenther, tied for the team lead with four goals this season, tapped in the winner on a pass across the front of the net from Clayton Keller.

Mikhail Sergachev, Lawson Crouse and Nick Schmaltz also scored for the Mammoth (5-2-0), who extended their franchise-best start at home to 4-0. Sergachev and Keller each had two assists, and Karel Vejmelka made 30 saves.

Cale Makar, Jack Drury and Martin Necas scored for Colorado (5-0-2), which has earned at least one point in each of its first seven games. Avalanche goalie Scott Wedgewood, who entered ranked second in the NHL with a 1.48 goals-against average, stopped 29 shots.

Necas scored the equalizer for the Avalanche with 2:16 left in regulation on a shot off Vejmelka’s helmet from a tough angle.

Sergachev gave the Mammoth a 3-2 lead when he stole the puck and slapped home an unassisted goal 5:20 into the third period.

Drury scored his first of the season 70 seconds into the third to make it 2-all.

Utah had a 15-7 advantage in shots on goal during a strong second period. Crouse scored on a one-timer and Schmaltz deposited a rebound on the power play after the Mammoth started the season 3 for 26 with the man advantage.

Colorado had a goal wiped off the board in the second when Valeri Nichushkin was ruled offside after a replay challenge, which seemed to sap the Avalanche’s momentum.

Makar opened the scoring with a slap shot just inside the blue line 5:29 into the game. The Avalanche had been 3-0 when scoring first.

Colorado didn’t score on its only power-play opportunity, falling to 3 for 26 this season.

The Mammoth next hit the road, visiting the St. Louis Blues on Thursday night.