DENVER — The Flyers have never started a season by winning their first two games on the road with both victories against Western Conference teams.

They were denied that accomplishment Saturday night at the Pepsi Center.

Colorado capitalized on defensive miscues, used its speed to its advantage, and defeated the Flyers, 5-2, as goalie Semyon Varlamov made 35 saves and Colin Wilson scored a pair of goals.

After a Christian Folin hooking penalty, Wilson iced the win by scoring on the power play with 3 minutes, 39 seconds left, putting the Avalanche ahead, 4-2. Nathan MacKinnon added an empty-net score.

The Flyers were trying to win their first two games of a season for the first time since 2011-12.

Making matters worse, they lost the services of left winger James van Riemsdyk, the team's marque free-agent signing in July, after he was hit near his right knee by a first-period clearing attempt and hobbled off the ice. He will be re-evaluated when the team returns home Monday.

"He's a big part of our team, a big body in our lineup," center Sean Couturier said. "He's a guy we want to see in our lineup."

"I'm concerned he wasn't able to come back," coach Dave Hakstol said. "I don't know the extent of it."

The Flyers came close to tying the score at 3-3 early in the third, but Varlamov turned aside five shots during a well-executed power play by the visitors.

"We got our chances….We were really moving it, and their goalie stood on his head," said defenseman Shayne Gostisbehere, whose team outshot the Avs, 37-35. "I mean, there's more to the game than just the power play. I think we could obviously clean up some things and get a little hungrier in front of the net."

With van Riemsdyk sidelined, the Flyers' four lines were scrambled the rest of the night, including his unit with Mikhail "Misha" Vorobyev and Wayne Simmonds.

Vorobyev's first NHL career goal can be described in one word: bizarre. Fact is, you can watch a couple thousand NHL games and not see a similar score.

In an innocent-looking play early in the second period,  Colorado defenseman Mark Barberio skated down ice after a loose puck and, at the side of the net, lost an edge and collided with Varlamov, sending him sprawling to the ice and the net wide open. An icing seemed in order until Varlamov touched the puck, then was wiped out by his teammate.

Vorobyev picked up the loose puck and tucked it into the empty net, knotting the score at 2-2 with 18 minutes left in the second.

A little over five minutes later, the Avs regained the lead, at 3-2, as Gabriel Landeskog tipped in MacKinnon's soft wrist shot while the teams were playing four-on-four. Landeskog got position on defenseman Travis Sanheim and tipped it home. The Flyers challenged for goaltender interference, but the goal stood _ the Situation Room in Toronto ruled that Sanheim pushed Landeskog into Elliott — with 12:42 to go in the second.

After the game, goalie Brian Elliott claimed Landeskog interfered with him.

"That's another one of the rules I really don't understand," Elliott said. "…He's in my crease; he impedes my arm coming across, and that is interference, I thought, in the rule book. (The refs) said they don't call it anymore; it's Toronto calling it, and that's all I know. I have to work to find out the rules this year."

Hakstol said he wouldn't have challenged the call "unless I was sure it was goalie interference."

Based on calls in recent years, Hakstol said he was confused as to "what is and what isn't" goalie interference.

"The player was in the crease and took away our goaltender's stick and did not fight to get out," Hakstol said. "That's what I saw and that's why I called it. I believe that's goalie interference."

About three minutes after Landeskog's goal, Elliott kept the deficit at 3-2. Somehow.

Late in a power play, Wilson broke through the defense and was in alone on Elliott. At the last second, he tapped a pass to Alexander Kerfoot on his left. Kerfoot appeared to have a tap-in into an empty net, but Elliott slid over and made his best save of the night.

In his first three seasons, Hakstol usually stayed with the same lineup after an impressive win. He made a surprising change Saturday, however, when he replaced defenseman Radko Gudas with Folin. Gudas, paired with Sanheim, played well in the Flyers'c 5-2 win in Las Vegas on Thursday.

Hakstol said Folin, signed as a free agent in the offseason after playing in Los Angeles, had earned a start because of a solid preseason.

But Folin struggled in his Flyers debut, and his turnover led to J.T. Compher's goal that gave Colorado a 2-1 lead with 7:02 remaining in the opening period. Compher scored on a one-timer from the left circle.

The Avs had taken a 1-0 lead just 1:35 into the game. Taking advantage of a two-on-one down low _ Folin was left alone — Wilson scored on a backhanded rebound.

Just like they did in the win in Las Vegas, the Flyers started slowly and then regrouped. Couturier, playing in his 500th career game, scored the equalizer on a rebound after Varlamov had stopped Travis Konecny on a breakaway with 12:30 left in the first.

"T.K. did a good job of reading the play and taking off," said Couturier, who missed most of the preseason because of a knee injury. "… I just tried to be there for the second opportunity."

Defensive breakdowns throughout the first period helped Colorado get 14 shots, many of them Grade A chances. They also had 14 shots in the second period as the Flyers' sloppy play continued.

Elliott kept the Flyers close in the first 40 minutes, and with 11 seconds left in the second, Varlamov made his best stop of the game — a great glove save on Sanheim's point-blank drive to keep the Avalanche ahead, 3-2.

The Flyers return from their two-game trip to face talented San Jose in their home opener Tuesday.

Hakstol said he thought his team was "much crisper" with the puck than in the opener, but added "there are a lot of things we can clean up."

Breakaways

Vorobyev on his first career goal: "I've thought about this for many years — scoring my first goal in the NHL. It was amazing."….Gostisbehere had four blocked shots and Folin had four hits…..Vorobyev won just two of seven faceoffs….Ivan Provorov played a game-high 26:56…Jake Voracek was minus-3….Matt Calvert had three assists and was plus-3 for the Avs.