The 21-year-old Mueller scored twice and Paul Stastny had his fifth goal in three games with two assists in a 5-3 victory over the Blues on Tuesday. Mueller has scored in all seven games after a trade from the Coyotes, totaling four goals and seven assists after having 17 points in 54 games with Phoenix.
"It's amazing what happens when you get a chance," said Mueller, the Coyotes' first-round pick in 2006. "It's one of those things where I wanted to come in here and show that I can contribute.
"I do belong playing in this league, and I'm trying to make people eat their words of what they've said in the past."
The Blues had quick goals to start the first two periods, with Alexander Steen matching the franchise record to start the game on his 20th goal just eight seconds in, and Patrik Berglund scoring at 34 seconds of the second to tie it at 2. Otherwise, backup goalie Peter Budaj was effective subbing for Craig Anderson, who got a break after making a franchise-record 23 consecutive starts.
"Obviously, when you don't play too much you feel out of the rhythm a little bit," Budaj said. "I just tried to be ready. You've been in net before, you know how it's done.
"I felt great in the third period."
St. Louis flopped in its first home game since Feb. 13, dropping to an NHL-worst 12-17-5 at the Scottrade Center, and the Avalanche outscored them 21-8 over four games for their first season sweep since 2005-06.
"I think it's just about us," Blues forward David Perron said. "They're a really good team, let's not kid ourselves. But if we played more of our game, we would have had better success against them."
Blues goalie Chris Mason gave up five goals on 24 shots after coming in 0-3 with a 7.22 goals-against average against Colorado.
Budaj was especially strong in the third period while the Blues had sustained pressure and outshot Colorado 14-6, but Chris Stewart's late goal put it out of reach.
Time is running out on the Blues' bid for a second straight late-season rally to make the playoffs. St. Louis dropped to 11th in the Western Conference, seven points behind eighth-place Detroit with 13 games to go.
St. Louis finished 9-1-1 last season to finish sixth.
"A lot's happened with two outs in the bottom of the ninth before, so we're not going to count ourselves out," forward David Backes said. "We play a lot of the teams that are ahead of us still and if we take care of our business I still like our chances.
"But losing games like these when we give our opponents a lot more than they take from us is going to be things that we'll kick ourselves in the end for."
Steen tied the mark set by Greg Paslawski on Oct. 29, 1985, against Washington when Budaj stopped his shot from the left boards but the rebound appeared to deflect off Avalanche forward T.J. Galiardi.
Colorado asserted itself later in the period, with Mueller getting a power play goal and assisting on Milan Hejduk's 18th of the season for a 2-1 lead.
The Avalanche went ahead by two on Stastny's rebound goal and Mueller's eighth of the season in a span of 1:29 midway through the second period. Perron scored on a rebound at 11:06 to cut the deficit to one.
- Mueller's start matches Theo Fleury (1998-99) for Colorado's longest streak since moving from Quebec, although Joe Sakic scored in 12 straight in 1988-89 for the Nordiques.
- Anderson was 15-8 with a 2.08 GAA and four shutouts during his starting streak. Only Martin Brodeur (33) and Roberto Luongo (26) have had longer consecutive-game runs in the NHL this season.
- U.S. Olympic silver medalists Erik Johnson and Backes (Blues) and Stastny (Avalanche) were recognized in a pregame ceremony.
- Steen has 12 goals in the last 17 home games.
- Stewart added an assist and finished with seven goals and 12 points in four games against the Blues, including two go-ahead goals.