Artturi Lehkonen helped the Colorado Avalanche secure a series sweep over the Edmonton Oilers on Monday, scoring in overtime for a 6-5 win.

Lehkonen ultimately secured the 4-0 Western Conference finals win for the Avalanche in fortunate circumstances, left with a simple finish after his elevated stick helped the puck elude Oilers goaltender Mike Smith.

With a tightly contested game heading to OT, Cale Makar's shot from the face-off was picked up by Lehkonen with what was argued to be a high stick. The puck deflected off Smith and left the 26-year-old with a simple finish to win the game and series and following a review, the goal was allowed.

Despite the fortune that came with the eventual winning goal, the Finnish winger cited his team's ability to fight back a 3-1 deficit in the third period as equally important.

"Cale took the shot and I've got to say, it landed straight on my blade and I basically had an empty net in front of me," Lehkonen told TNT post-game.

"It was a great comeback win, for sure. We were talking during the second intermission that we just had to find our game and we could pull through this."

Mikko Rantanen stunningly put the Avalanche ahead with 5:14 remaining in regulation, in what was a four-goal period for the Western Conference's first seed.

After the Oilers let a 3-1 lead slip with their season on the line, Leon Draisatl and Connor McDavid combined to equalise, capitalising on Danell Nurse's defensive play to spring them into transition.

Advancing to the Stanley Cup Finals for the first time since 2001, the Avalanche will now face the winner of the series between the Tampa Bay Lightning and New York Rangers.

Artturi Lehkonen's overtime goal against the Vegas Golden Knights propelled the Montreal Canadiens to their first NHL Stanley Cup Final since 1993 on Thursday.

The Canadiens ended their 28-year wait, punching their ticket to the NHL's showpiece thanks to Lehkonen's goal less than two minutes into OT in Game 6 of the semi-final series.

Just like Tyler Toffoli against the Winnipeg Jets in overtime, Lehkonen scored 99 seconds into OT to oust the Golden Knights. According to Stats Perform, the Canadiens are the first team in NHL history to score two overtime goals at the exact same time in a single postseason.

Not much was expected of the Canadiens in the NHL playoffs, having entered the postseason with the worst record but Montreal have won 11 of 13 games since sensationally overturning a 3-1 deficit against rivals the Toronto Maple Leafs in the first round.

The Canadiens – 24-time champions as they make their NHL-leading 35th Stanley Cup Final appearance – will face either defending champions the Tampa Bay Lightning or the New York Islanders.

"We wouldn't be here right now if we didn't believe," said Canadiens goalie Carey Price, who stopped 37 shots. "We've believed this whole time and obviously we're ecstatic and we have a lot of work left to do."

Lehkonen added: "Just trying to go high and hit the net. We're trying to keep it going one game at a time and not think things too much far ahead.

"I feel like we showed up today and it's a big win for us and we have four more to go."