Nathan MacKinnon had a goal and two assists, Alexander Kerfoot and Mikko Rantanen also scored for Colorado.
Semyon Varlamov had 31 saves for the Avalanche, who bounced back from losing to Arizona on Wednesday to beat another Eastern Conference power. Colorado swept two-time reigning champion Pittsburgh and split the season series with Washington.
Matt Martin, Roman Polak and James Van Riemsdyk had goals and Calvin Pickard stopped 24 shots for Toronto.
The Avalanche got a break in overtime when Connor Brown was given a minor for interference. Colorado had several chances, including MacKinnon hitting a post, before Compher beat Pickard with 9 seconds left on the power play.
The Avalanche took a 3-2 lead when Kerfoot scored his 10th goal of the season at 4:34 of the third period. Toronto pressured for the tying goal and finally got it when Van Riemsdyk scored at 18:05 with Pickard off for an extra skater.
MacKinnon gave Colorado a 1-0 lead with his 16th goal midway through the first period. Toronto tied it when Martin’s centering pass from down low bounced of Blake Comeau’s skate and in at 14:55.
Rantanen again gave Colorado the lead with his one-timer on a pass from behind the net from MacKinnon at 10:29 of the second period. It was Rantanen’s 12th of the season. Toronto quickly answered when Polak’s soft shot from a sharp angle beat Varlamov at 14:04.
NOTES: Rantanen has points in eight straight games, the longest streak of his career. … Toronto C Nazem Kadri was scratched with an upper-body injury. Kadri has 13 goals and 10 assists but has not recorded a point in 11 straight games. … The Avalanche recalled D Andre Mironov from San Antonio of the AHL on Thursday. He was a healthy scratch Friday. … Pickard was recalled from the AHL because backup Curtis McElhinney is out with a lower-body injury. … Colorado has not allowed a power-play goal in its last 10 games. The Avalanche have killed off 30 straight penalties in that span.
Maple Leafs: Make their first trip to Vegas to play the Golden Knights on Sunday.
Avalanche: Host the New York Islanders on Sunday night.
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