DENVER — Superstar forward Nathan MacKinnon thought he had the game tied just 2:37 into the third period with the Avs down a goal. But for the second time in as many games, an offside challenge wiped off a crucial tally for Colorado, which suffered a 2-1 Game 7 defeat at the hands of the Seattle Kraken on Sunday.

The Kraken will advance to Round 2 and take on the Dallas Stars. And the Avs, who have dealt with all sorts of adversity in 2022-23, see their season come to an end in the first round for the first time since 2018.

“Tough year overall. During the season we’re going to say all the right things,” Mackinnon said. “But it’s hard missing guys.

“I’m definitely happy with the way we battled all season. Even tonight. I thought we played a really great game. Just couldn’t find the back of the net.”

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The Avalanche outshot the Kraken 34-27 but could only get one past goalie Philipp Grubauer, who defeated his former team in his first playoff series with Seattle. The lone tally for Colorado was a power-play goal by Mikko Rantanen. The goal-scorer ended the series with seven goals in as many games after setting a regular-season Avalanche record with 55 goals.

But despite that, Rantanen still feels the team had more to give. And it’s largely because of the injuries they dealt with all season. In Game 7, Colorado was without Darren Helm, Andrew Cogliano and Josh Manson because of injuries. Valeri Nichushkin also remained out for personal reasons, and Gabriel Landeskog has not played all year.

“Weirdest season of my career, for sure,” Rantanen said.

The Avalanche stormed out of the gate in the first period. Feeding off the crowd’s energy, Colorado outshot the Kraken 16-6 in the opening 20 minutes and had several chances to score the first goal. But Grubauer was up to the task. Nathan MacKinnon was robbed twice by Grubauer in the first period alone, who was under siege from the Avs’ top line of Artturi Lehkonen, Rantanen and MacKinnon the entire night.

With that line on the ice, Colorado outshot the Kraken 15-7 and had a 35-12 shot attempt advantage. MacKinnon led the way with nine shots.

But that was the problem the defending champs faced in each of the seven games. MacKinnon, Rantanen and the top defense pair of Cale Makar and Devon Toews scored or assisted on every goal the Avs scored in the series. Their depth was seemingly dissipating by the game — just as it was for long stretches during the regular season.

“I don’t think anybody’s gonna be looking back and thinking that everybody didn’t leave it out there,” Makar said.

Despite the early surge from the Avs, Seattle again was on the board first. The Kraken became the first team since the 2004 Toronto Maple Leafs to score first in each game of a series that goes the distance. The goal, which was the first of two from forward Oliver Bjorkstrand, was a tough break for the Avs. Bjorkstrand was in the corner behind the goal line and attempted to center it to Brandon Tanev in the crease. The puck instead deflected off Colorado’s Ben Meyers and past goaltender Alexandar Georgiev.

Bjorkstrand would then enter the Avs zone with speed and wire it past Georgiev from the circle just 3:58 later. It was his first two goals of the series, and they couldn’t come at a better time for the Kraken, who have scored the first two goals of a game three times. Bjorkstrand became the 15th Kraken player to score against Colorado.

It was pretty impressive what they’ve overcome,” Avs coach Jared Bednar said of his team’s season. “Some years it’s a little tougher than others, and this was a tough one. I’ve been in the game at the pro level for quite some time, and there’s a lot of stuff that happened this year that you just can’t plan for.”