The crowd chanted, "End of streak! End of streak!" over the final minutes after P.A. Parenteau's 10th goal of the season made it 6-2.
Bryan Bickell's goal with 11:07 pulled the Blackhawks to 5-2 and he nearly scored again from the same spot 90 seconds later, but Varlamov smothered the shot — and that was that.
The teams got into a scuffle with 5:04 left after Bickell squared off with Gabriel Landeskog, who had checked Keith in the back.
Chicago's Jonathan Toews got the scoring started when he knocked the puck past Varlamov after a turnover on a give-and-go with forward Marian Hossa, who returned from an upper-body injury.
But Colorado scored the next five goals.
Duchene's goal between Crawford's legs made it 2-1. Just 33 seconds later, Mitchell scored on an assist from O'Reilly, who was signed to a two-year $10 million deal last week after the Avalanche matched Calgary's offer sheet following a nasty contract dispute.
O'Reilly's goal came on a slap shot from the top of the right circle 4 seconds into another power play. Duchene set him up with a pass after Stastny won the faceoff.
Duchene got his third assist when he dug out a loose puck from the boards in a scramble with Keith and kicked it out to McGinn, who put made it 5-1.
Remarkable though it was, the streak had become somewhat of a burden for the Blackhawks.
"It's gained a lot of momentum over the last little while and our opponents, they treated it like it was a very important game," Quenneville said. "You look at the standings and everyone has a meaningful game, but it seemed like there was added incentive as we've gone along. We welcomed the challenge."
After a while, it seemed the streak had taken on a life of its own.
"I'd say the last handful of games the talk about it kind of got out of control," Toews said. "The guys in our locker room, we always focused on the same thing, being prepared to play our team game. We never really got distracted by that. Maybe it does take a little bit of pressure off us and we can sit back and look at the good things we've done."
The Blackhawks' run comes with somewhat of an asterisk because they actually lost three games along the way — all in shootouts. Under NHL rules, that's still worth a point, but that makes it different from what the Flyers accomplished nearly a quarter-century ago.
During the Flyers' streak there was no overtime until the playoffs, and the shootout was still a far-off creation. If the teams were tied after 60 minutes, that's how it ended and each got a point.
Nowadays, both teams still receive a point if the game is tied at the end of regulation. Then, the team that scores in a five-minute, four-skaters-a-side overtime period or wins the shootout gets an extra point.
"It's over," Crawford said. "Move on to the next game."
NOTES: Avalanche D Erik Johnson returned to the lineup after missing 11 games with a head injury. ... The Blackhawks were without F Patrick Sharp, who left Wednesday's home win over the Avalanche with a shoulder injury after being checked along the boards by Colorado's Ryan O'Byrne.
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