DENVER (AP) - Mikko Rantanen had two goals less than a week after agreeing to a contract with Colorado, Joonas Donskoi scored twice in his debut and the Avalanche beat the Calgary Flames 5-3 on Thursday night.
Rantanen was a restricted free agent heading into the summer and he remained in his native Finland while contract negations dragged on through training camp. The parties finally agreed to a six-year, $55.5 million deal on Saturday night and Rantanen joined the team on Sunday, four days before the start of the season.
He scored a go-ahead goal in the first period and added the eventual decisive score on the power play late in the second period, minutes after J.T. Compher gave Colorado a 3-2 lead.
Mark Giordano scored 16 seconds after Rantanen's second goal.
Johnny Gaudreau and Sean Monahan each had a goal and an assist for Calgary. David Rittich had 26 saves for the Flames, who started the season the same way last season ended _ with a loss.
The Avalanche defeated Calgary in the first round of last season’s playoffs, beating the Western Conference's top seed in five games.
Donskoi got Colorado off to a quick start with a power-play goal 5:59 in, and the teams traded goals the rest of the period.
Gaudreau's goal 1:50 into the second period tied it and Donskoi scored into an empty net with 1:09 left in the third.
Colorado goalie Philipp Grubauer had 26 saves.
NOTES: Calgary LW Milan Lucic was given a game misconduct late in the second period. ... The Flames announced Thursday they had signed general manager Brad Treliving to a mult-year contract extension. Treliving is in his sixth year as the club's GM. ... Avalanche D Conor Timmins made his NHL debut Thursday night. He was Colorado's second round pick in the 2017 draft. Fellow defenseman Cale Makar had an assist in his first regular-season game. Makar played in 10 playoff games last spring.
Flames: Host the Vancouver Canucks in their home opener Saturday night.
Avalanche: Host the Minnesota Wild on Saturday night.