CALGARY — The shock was fading, but the sting wasn't for the Calgary Flames.

The top seed in the NHL's Western Conference was still coming to grips Monday with exiting the first round of playoffs in five games at the hands of the eighth-seeded Colorado Avalanche.

The Flames were an offensive juggernaut that gave up the fewest shots against per game in a 107-point season, which was their best since winning the Stanley Cup in 1989.

But Calgary was the opposite in a quick post-season elimination.

"We did a lot of good things to put ourselves in a position to play longer than we did," Flames general manager Brad Treliving said. "We didn't look like the team we looked like for 82 games."

"To have the type of regular season that we had, second overall in the league, 107 points, 50 wins and for it to end as quickly as it does, it seems like you wasted a lot of things and there's a lot of irrelevance of the regular season.

"That's part of becoming a good team. You raise your own expectations."

The Avalanche hit the playoffs at full gallop, going 8-0-2 to clinch a playoff spot in their second-last game of the regular season.

The Flames didn't feel the same urgency down the stretch.

Calgary went 6-4 after bagging a playoff spot March 17, but still locked down top spot in the conference with three games remaining.

That may account for Avalanche's higher gear and Calgary's inability to counter it in the playoffs

"Colorado was a team that was coming in with a lot of momentum," said Flames captain Mark Giordano, a Norris-Trophy nominee.

"For me, it was their ability to get momentum and keep going throughout the game. We couldn't find a way to get that momentum back."

Calgary head coach Bill Peters, hired one year ago, indicated he'd do things differently in those "meaningless" Games 80, 81, 82 of the regular season, but wouldn't expand on that.

"That was a unique set of circumstances," he said. "That's something we'll definitely talk about."

Calgary's 289 goals was second only to the Tampa Bay Lightning and tied with the San Jose Sharks.

But the Flames didn't produce more than two goals per game in four straight losses to bow out. Two of those games they led in the third period only to lose in overtime.

Leading goalscorer Johnny Gaudreau had one assist in the series. Top-line centre Sean Monahan had one goal.

"Playoff time came and I didn't find the net there a couple of times when I should have," Gaudreau said. "It's not what you hope for, but something to learn from."

If not for goaltender Mike Smith's 188 saves in the series, Calgary would have been dispatched even more decisively.

"We blew some 'A' goaltending performances," Treliving stated.

Injuries were not a large factor in Calgary's swoon.

Monahan played with a "cracked thumb" at season's end. The malady was minor enough that Monahan was considering playing for Canada at the upcoming world championship.

Peters was against it.

"I don't think Monny is healthy enough to go in my opinion," the coach said.

"He's got to make a decision here whether he wants to continue to play or take the time to heal to get to 100 per cent and then take advantage of his summer."

Calgary's best playoff performers — goaltender Mike Smith and forwards Matthew Tkachuk and Sam Bennett — are among Treliving's biggest decisions in the off-season.

Smith, 37, and fourth-line forward Garnet Hathaway will enter unrestricted free agency. Tkachuk, Bennett and Andrew Mangiapane, ranging from 21 to 23 respectively, are scheduled for restricted free agency.

Defencemen T.J. Brodie, Travis Hamonic and Mike Stone are all entering the last year of their contracts.

The Flames also have a relationship to mend with winger James Neal, a 31-year-old playoff veteran who was a healthy scratch in Game 5 because of lack of production.

"Our team underachieved, and I think from top to bottom, at the most critical time of the year," Treliving said. "We've got to figure out why. Right now, I don't have the why for you, but we'll get to that in time.

"I tell our guys all the time 'the regular season is where you make your money. The playoffs is where you make your legacy.'"