Darren Helm scored the winning goal with 5.6 seconds left to lift the visiting Colorado Avalanche over the St. Louis Blues 3-2 on Friday, clinching their second-round Western Conference playoff series in Game 6.

Helm's slap shot from the top of the left circle gave the Avalanche a 4-2 victory in the best-of-seven series. Colorado moves on to face the Edmonton Oilers in the Western Conference finals in its first trip to the NHL's final four since 2002.

The goal was Helm's first in 10 playoff games this year and just his eighth in 69 career postseason games.

"Playoff time, that's what you need," said Colorado's J.T. Compher, who added two goals. "Plenty of times during the year in the playoffs our top lines have gotten the job done. It felt good for the third and fourth line to help win tonight."

"Obviously the job is not finished, but it's a great accomplishment for sure. Nice to get over this hump for sure. Definitely felt like we outplayed them in this series."

Avalanche goalie Darcy Kuemper made 18 saves for the win.

Colorado center Nathan MacKinnon said, "Obviously the job is not finished, but it's a great accomplishment for sure. Nice to get over this hump for sure. Definitely felt like we outplayed them in this series."

Justin Faulk and Jordan Kyrou scored for the Blues, and Ville Husso stopped 36 shots.

Colorado outshot St. Louis 39-20. The Avalanche pinned the Blues in their own zone during the first period and maintained heavy pressure. Mikko Rantanen had a point-bank opportunity on his backhand, but Husso denied him.

Nazem Kadri got in free on a two-on-one break, but he missed his shot.

A power play late in the opening period helped the Blues find an offensive flow. They didn't convert, but they gained momentum and took a 1-0 lead with one minute left in the period.

Robert Thomas passed to Faulk coming down the middle. Faulk shot from the slot as Vladimir Tarasenko created a screen on Kuemper.

Colorado tied the 1-1 game 5:19 into the second period after Manson doubled back from the left corner. His shot rebounded to Compher in front of the net for the easy conversion.

The Blues countered with a two-on-one rush to take a 2-1 lead at 9:34 of the middle period. Brayden Schenn pushed the puck up the right wing and set up Kyrou's goal from the center edge of the left circle.

The Blues had multiple chances to add on, but Alexei Toropchenko hit the post, Manson slid into the crease to stop Kyrou's shot with Kuemper out of the net, and then Kyrou misfired on a breakaway.

Those missed opportunities stung when the Avalanche tied the game 2-2 on Compher's power-play goal off the right wing at 10:18 of the third period. That set the stage for Helm's last-minute heroics.

"It's a tough way to end it," Blues coach Craig Berurbe said, "but that's the way it goes. Our guys battled hard."

--Field Level Media