ST. LOUIS -- St. Louis general manager Doug Armstrong ended a Thursday morning news conference by saying that Alexander Steen had to leave, "to go out and earn his money," after the left wing had signed a three-year, $17.4 million contract extension.
Brendan Gallagher scored for Montreal, which began a season-high six-game road trip. It was his first goal in 12 games.
Steen started a three-goal outburst in the first period with a short-handed goal at 4:20. He scored again at 7:55 to make it 2-0.
Steen gave his teammates credit for the win.
"We played a solid game throughout the whole 60 minutes," he said. "We came out with a lot of jump. I felt like we dictated from the early going."
Stewart capped the early blitz with his 10th goal of the season at 13:33. It was his fifth in as many games. The Blues had been outscored 6-1 in the first period in their three previous games.
Halak continued his mastery of his former teammates. He has an 0.98 goals-against average and a .960 save percentage in four starts against Montreal. He stopped Michael Bournival on a partial breakaway in the early going and made 12 stops in the final period.
"It's been good, for now," he said. "But we will see them again. It's great to (be) 4-0. But for us, it was all about the two points."
Montreal goalie Carey Price gave up three goals on the first eight shots and fell to 16-11-2 as the Canadiens dig themselves a deep hole and never quite recovered.
"We didn't show up tonight," Montreal coach Michel Therrien said. "It was simple, our work ethic was not there. I'm disappointed in our performance -- no effort. This was a bad game for us."
"It was a period that we just weren't ready for," he said.
Montreal C Daniel Briere was a healthy scratch for the first time this season. .... Schwartz returned to the lineup after missing two games with an upper-body injury. ... The Blues beat Montreal 4-1 in the teams' previous meeting in St. Louis on March 10, 2011. ... The Blues will play 12 of their next 13 games against Western Conference opponents. ... St. Louis LW Brenden Morrow picked up his 300th career assist on Stewart's first-period goal. ... Montreal D Alexei Emelin was on the ice for all three of the Blues' first-period goals. ... The Canadiens' previous win over St. Louis came on Jan. 4, 2007.
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ST. LOUIS, MO - DECEMBER 19: Peter Budaj #30 of the Montreal Canadiens takes warm up shots from Ryan White #53...