However, the Capitals were upset with Avalanche forward David Koci's hit on Mike Green late in the second period that knocked the defenseman out of the game. Koci checked Green into the glass behind the Washington net and received a boarding major and a game misconduct.
He also drew the ire of Washington coach Bruce Boudreau.
"Fifteen feet he saw Green's No. 52 and it didn't stop him one iota from hitting him in the back and going for the head," Boudreau said. "So I hope they throw the book at him.
"I've faced David Koci an awful lot, he might be a nice guy, I have no idea. I'm glad he's making a living, but if this is any other game, he gets on the ice for the first three minutes, he gets into his fight with the guy and then he sits at the end of the bench, so what good is he? It shows what we have to get rid of to have a good game."
Green, who had several stitches over a black left eye, said he didn't see Koci coming.
"I couldn't see him, so it must have been from behind," Green said. "He's a big guy and he has to be more careful."
Fellow defenseman John Erskine got a misconduct and a fighting major for going after Koci.
"You've got to stand up for your teammate," Erskine said.
The Capitals took a 2-0 lead on first-period goals by Fleischmann and Knuble, then blew it open in the second. Steckel scored 4:02 in, and then Fleischmann and Bradley added goals 3:11 apart to bury the Avalanche.
On Saturday against Toronto, Washington took a 2-0 lead in the first period but lost 6-3. The players took that into mind when they came out for the second period.
"We knew if we didn't keep playing like we did in the first period, it might end up like last game," Fleischmann said.
It could have been a bigger blowout when Brooks Laich knocked in a puck 34 seconds after Knuble scored in the first, but the goal was waved off when a video review determined the puck was kicked into the net.
"We had some breakdowns and they capitalized," Avalanche coach Joe Sacco said. "That's the type of team they are. They're opportunistic."
Six goals was more than enough for Theodore, who faced his former team for the first time. Theodore, who played two-plus seasons with Colorado and led the Avalanche to the Western Conference semifinals in 2008, won for the fourth time in five games.
T.J. Galiardi scored a power-play goal for Colorado with 8:39 left, spoiling Theodore's shutout bid.
"Shutouts are good, but the win is the main thing," Theodore said.
Craig Anderson allowed five goals on 21 shots before being replaced by Peter Budaj at the start of the third period. Budaj gave up Backstrom's power-play goal that finished the scoring late in the frame. He made three saves.
"They've got a lot of offensive firepower and their guys are going to score when they have opportunities," Anderson said. "For us, we just didn't play as well as we could."
Colorado's Milan Hejduk (knee) and Marek Svatos (groin) were scratched. ... The Avalanche honored former player Mike Keane before the game as part of their alumni series this season. ... Washington forward Alex Ovechkin has eight points in his last five games. ... Colorado is 7-2-1 against Eastern Conference teams, 3-1 home.
Copyright by STATS LLC and The Associated Press
Arena: Pepsi Center Location: Denver, Colorado
Referees: Brad Watson, Gord Dwyer Linesmen: Thor Nelson, Mark Wheler
Attendance: 14,172 (78.7% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Tomas Fleischmann (12)
Assists: Eric Fehr, Kyle Wilson
Mike Knuble (6)
Assists: Alex Ovechkin, Nicklas Backstrom
David Steckel (2)
Assists: Matt Bradley, Chris Clark
Tomas Fleischmann (13)
Assist: Kyle Wilson
Matt Bradley (6)
Assists: John Erskine, Chris Clark
T.J. Galiardi (4)
(Power Play) Assists: Matt Duchene, Kyle Quincey
Nicklas Backstrom (11)
(Power Play) Assists: Tom Poti, Brendan Morrison