Many of Mikko Rantanen’s greatest moments have come in a Colorado Avalanche sweater. It’s just that the most defining moment of his career came at their expense.

It wasn’t enough that the Dallas Stars were trailing by two goals. It was also the fact that Rantanen scored a hat trick in a string of four unanswered goals that saw his current team, the host Stars, eliminate his old team, the Avalanche, in a 4-2 win Saturday in Game 7 of the Western Conference quarterfinals at the American Airlines Center.

“Obviously, the feeling was incredible to win a series,” Rantanen said in his postgame media availability. “This series was not exactly what I expected. I expected a seven-game series, even before Game 1. The ups and downs in the series. … Belief was there with the group the whole time. Obviously, I was able to make a pay to get the first one and the crowd started to roll.”

The Stars, attempting to reach the conference finals a third straight time, will advance to the semifinal round in which they will await the winner of series featuring the St. Louis Blues and Winnipeg Jets. That encounter will be decided Sunday in Game 7 in Winnipeg.

Soon, the Stars’ collective focus will shift to another Central Division foe. But for now? The attention before, during, and after the game, was on Rantanen.

Part of what made the Avalanche-Stars series arguably the most intriguing first-round series in either conference was the fact it placed two 100-point teams that are in championship window against each other. But, it also came with several subplots with the notable being the team that traded quite a bit to land Rantanen — with the hope he could win them a Stanley Cup now — needed him to defeat the team that he won a championship with back in 2022.

With one assist through the first four games, there was a discussion about if the Stars could manage to win with a sputtering Rantanen on top of the fact they were already without two of their best players in defenseman Miro Heiskanen and forward Jason Robertson.

Rantanen responded with a three-point performance in Game 5, and a four-point performance in Game 6 only to then have a hand in each goal on Saturday. His first goal came on the power-play with 12:12 remaining in the third period when he found enough space to fire a wrist shot that beat MacKenzie Blackwood.

Then came the game-tying goal and the significance it carried. The Stars went on the power play went Avalanche forward Jack Drury was called for holding. Drury part of the trade package the Carolina Hurricanes used to get Rantanen in late January before they would trade him to the Stars.

Drury’s penalty opened the door for Rantanen to score a game-tying goal that might be one of, if not, his signature salvo. Rantanen skated into the Avalanche zone in a 1-on-3 before he split two players before going around the net for a wrap-around goal that went off the skate of Samuel Girard with 6:14 left.

Three minutes later, the Stars received another power-play opportunity that saw Rantanen along with another former Avalanche forward in Matt Duchene work together to find Wyatt Johnston for the game-winning goal.

In the final minute, the Avalanche pulled Blackwood in the attempt to grab a late goal and force over time. Instead? Stars goaltender Jake Oettinger withstood a barrage that officially ended when Stars forward Tyler Seguin got the puck out of the zone only for Rantanen to skate in on an open net for the hat trick with three seconds left.

“I couldn’t care less who scored for them, I really couldn’t,” Avalanche captain and left winger Gabriel Landeskog said when asked about what it was like to watch Rantanen score a hat trick. “Mikko is one of my best friends and I love him, but I couldn’t care if he scored or if somebody else scored.”

For eight full seasons, Rantanen was part of a homegrown movement that saw the Avalanche go from finishing with what was then the worst record in the salary cap era back in 2016-17 to become a perennial favorite to win the Stanley Cup, which did they did in 2023, while also becoming a model for the need to build through the draft.

Building through stars such as Cale Makar, Nathan MacKinnon, Landeskog and Rantanen allowed the Avalanche to become a success. As did the moves they made to get other key figures like Valeri Nichushkin and Devon Toews.

Like all teams in a championship window, the Avs were facing the prospect of possibly making a difficult decision. They had yet to agree to a new contract with Rantanen, who was a pending unrestricted free agent. Then, came the blockbuster trade that few throughout the league saw coming.

The Avalanche traded Rantanen in a three-team trade that saw them get Martin Necas and Drury along with two draft picks. Rantanen’s time with the Carolina Hurricanes was limited to just two goals and six points in 13 games.

Despite the fact the Hurricanes are also among that cadre of championship contenders, Rantanen struggled to find cohesion in Raleigh. Rather than run the risk of watching leave for nothing in free agency, the Hurricanes put out feelers to a few teams with the Stars being one of them.

A long-time admirer of Rantanen, the Stars packaged two first-round picks, three second-round picks and former prized prospect Logan Stankoven to get Rantanen. They then signed him to an eight-year contract worth $12 million annually.

“It’s two things: It’s where our team’s at, and it’s Mikko Rantanen,” Stars general manager Jim Nill told ESPN back in March.

Rantanen finished the regular season with five goals and 18 points in 20 games prior to the showdown with his former team.

Not only did Rantanen’s hat trick condemn his former team to their second first-round exit since winning the Stanley Cup, but it continued a theme of former Avalanche eliminating their previous employers.

The Avalanche and Stars faced each other in last season’s Western Conference semifinal that saw Duchene, a former Colorado first-round pick, score the game-winning goal.

A year later, it was another former Avalanche first-round pick who delivered the devastating blow.

“It seems pretty fitting,” Johnston said about Rantanen. “Obviously, we want to win for each other and I think that goes a little extra when it’s a guy like that who is such a big part of our team and was there for a long time and everyone knows the trade that went on. It’s so awesome. We’re so happy as a group for him.”

As if Rantanen scoring a hat trick in a four-goal comeback wasn’t enough, there’s also the fact that this is now the ninth consecutive Game 7 that Stars coach Peter DeBoer has won his career.

DeBoer’s nine wins in Game 7s broke a tie with Darryl Sutter for the most in NHL history. It was also DeBoer’s third game 7 wins with the Stars.

“I felt something was going to happen,” DeBoer said. “But I could not have predicted that.”