It was the second time this season Stewart completed the Gordie Howe hat trick -- a goal, an assist and a fight. He was put into the fighting role when the usual enforcer, David Koci, suffered a broken right hand in a fight in the first period.
"Not many guys can fight and I figured I'd step up and get the team going," he said.
Stewart's fight with B.J. Crombeen came 2 seconds after a Colorado flurry in the first 6 minutes, 34 seconds of the second period blew open a close game. With the game tied at 2, Colorado got goals from Stewart, Stastny and Yip 4:09 apart to take a 5-2 lead and chase Chris Mason, who allowed five goals on 15 shots.
"We thought [we] had things going and they get three goals," Blues defenseman Darryl Sydor said. "It was down hill from there."
Stewart's 18th goal of the season was the winner, but according to Sydor the puck never touched the Colorado forward. Ryan Wilson took a shot from the point and the puck appeared to go off Stewart and past Mason, but Sydor said the puck deflected off him.
"It hit the inside of my leg and went in," he said. "That's the way it's been this year."
The Avalanche have a different view of this season. After finishing last in the Western Conference this year Colorado is tied with Vancouver for first in the Northwest Division despite using 10 rookies. Yip, who won an NCAA title with Boston University last year, made his NHL debut Dec. 18 and has 11 goals and 18 points in just 22 games.
"I've just been keeping it simple," he said. "I've been lucky to play with some great players."
Anderson was briefly down on the ice in the second period after taking a puck in the upper chest on a shot by Andy McDonald. A Colorado trainer attended to him in the crease, but Anderson stayed in the game.
He showed he was OK by keeping St. Louis off the board the rest of the way, thanks to a little good fortune.
The Blues thought they had cut the lead to 5-3 when T.J. Oshie tipped in a rebound midway through the second period, but the goal was disallowed on a hooking penalty called on Oshie.
The penalty summed up the second period for St. Louis.
"We came out in the second period knowing that we had to elevate our play and they elevated before we did," Blues coach Davis Payne said. "They jumped us with goals when we made a coverage mistake, then their goals came off two turnovers."
The game started well for St. Louis. Eric Brewer made it 1-0 with a wrist shot at 3:34 of the first, but 28 seconds later Galiardi tied it with a point-blank shot that beat Mason over his left shoulder.
St. Louis took a 2-1 lead when Erik Johnson beat Anderson with a shot to the short side with 12:01 left in the first. Yip tied it on the power play with 3:18 left in the first period.
"We got a big goal late in the first period, but nobody was happy with our effort in the first," Stewart said. "We got a quick goal in the second and that fed us."
Johnson's goal was his first since Nov. 30 at Columbus, a span of 31 games. ... Colorado C Ryan O'Reilly (bruised foot) missed his first game of the season. ... Ty Conklin had 18 saves for St. Louis.