For one period, the new Avs looked too much like the old Avs. A flat start at home, a smattering of boos when the first-period horn sounded, a road team walking back to the dressing room with some swag in their steps. But it was all totally different for the next 40 minutes.

In that span, the Avalanche bullied the defending Stanley Cup champion Los Angeles Kings in every aspect of the sport and wound up winning its home opener 3-1 on Tuesday night before a sellout crowd of 18,007 loud fans at the Pepsi Center.

Third-period goals by Gabriel Landeskog, David Jones and P.A. Parenteau overturned what had been a tenuous 1-0 Kings lead entering the period, and goalie Semyon Varlamov was outstanding all night for the Avs.

“That was the best crowd I’ve ever played in front of at the Pepsi Center,” said Landeskog, whose goal one minute into the third period tied the game. “We knew that if we kept pushing, we thought we could get another.”

The win did come at some cost in personnel, however. Left wing Steve Downie suffered a right knee injury and did not return, with no word on his short-term prognosis.

Colorado started out terribly, but Varlamov kept it in the game with some outstanding work in net.

The Avalanche had a 5-on-3 power play for 1:29 late in the second period, its perfect chance to get the game tied heading to the third. But the Avs couldn’t do it, losing a key faceoff midway through the advantage that got everything in disarray.

The Avs finally woke up in the third, though, and their top forwards supplied the energy. Matt Duchene and Paul Stastny set up goals. Duchene helped set up Landeskog’s first goal of the year, keeping a puck alive behind the net and backhanding it back out front where Landeskog put a quick snap shot to the far post.

“I thought we showed a lot of resiliency,” Avs coach Joe Sacco said. “The first period, I wouldn’t call it ideal, from our standpoint. But we gathered ourselves. … Once we got the (first) goal, you could see the guys start to feed off the momentum swing, and the energy was good on the bench. We were getting pucks deep and coming in waves after that.”

The Avs got a power play shortly thereafter, and Jones made it 2-1 with a wrist shot past Jonathan Quick from about 25 feet, after a pass from Stastny.

Newcomer Parenteau got his first goal as an Av with a bit more than 11 minutes left, on a goal that wouldn’t have been possible without the hustle of Landeskog.

The Avs’ captain stole a puck near the blue line and dumped it back down low, where defenseman Erik Johnson, pinching down deep, grabbed it and fed a pretty backhand pass out front. Parenteau was there in the right crease and put it past Quick to make it 3-1.

“We just kept coming, and we just needed that one goal, I think, to get really going,” Parenteau said. “It was an exciting third period, that’s for sure. We played a good game; maybe a little flat at the start, but we kept going. It felt great to get that first one here. (Johnson) made a great play getting the puck out front with that pass.”

The Avs nearly lost Duchene to injury when he took a slap shot to the face in the third. It cut him, but he returned to finish off a solid performance.

“I think I’d take a scar for every win we could get,” Duchene said. “If I could take a scar for every one, I’d end up looking like Gerry Cheevers in the end.”

Adrian Dater: 303-954-1360, adater@denverpost.com or twitter.com/adater

Avs Recap

The Post’s three stars.

1. Gabriel Landeskog. Avs captain scored the tying goal and helped set up another.

2. Semyon Varlamov. Avs goalie was outstanding, allowing only a late first-period goal that wasn’t much his fault.

3. Matt Duchene. Avs center looked strong and fast all night and was rewarded with a third-period assist on Landeskog’s goal.

What you might have missed.

The Avs honored the memory of Aurora shooting victim and KKFN intern Jessica Redfield Ghawi with a plaque at the seat she occupied for games.

Up next.

Columbus, Thursday at 7 p.m., Pepsi Center.