MONTREAL -- The Montreal Canadiens handed the defending Stanley Cup champion St. Louis Blues their first regulation loss of the season with a 6-3 win at Bell Centre on Saturday.
Brendan Gallagher had a goal and two assists, including one on Artturi Lehkonen's goal at 7:30 of the third period to put Montreal ahead for the third time, 4-3.
Gallagher gave the Canadiens their first two-goal lead of the season when he made it 5-3 at 11:56.
[WATCH: All Blues vs. Canadiens highlights]
"We talked after 40 minutes that we just want to continue what we were doing," Gallagher said. "We were having success playing that certain way, nothing needed to change. Even when we got up, it was the same way. You know, obviously [Lehkonen] scores the big goal, but we just wanted to keep playing the same way, keep doing the same things, and I think we got rewarded for it tonight."
Max Domi scored into an empty net to make it 6-3 at 17:32.
Carey Price made 26 saves for Montreal (2-1-2), which had lost two games in a row.
Jonathan Drouin had a goal and an assist to extend his season-opening point streak to five games (two goals, four assists).
"We know who we were playing," Drouin said. "We were playing a team that's won the Stanley Cup, that's won a lot of battles in the past, and they know how to win. So if we didn't bring it to them, they were going to bring it to us and they're probably going to get that win. So we wanted to be the first team to get after this third period and make sure we were controlling the pace."
Video: STL@MTL: Drouin nets wrister off the post and in
Brayden Schenn had a goal and an assist, and Sammy Blais and Vince Dunn scored for St. Louis (3-1-1), which had won three in a row.
"We didn't bring out our best effort in the third," Schenn said. "We turned over pucks, and I think they just wanted it more than us in the third."
Jordan Binnington made 31 saves for the Blues.
"They played better, they played harder than us, that's what it boils down to," St. Louis coach Craig Berube said.
Tomas Tatar scored at 12:59 of the first period to give Montreal a 1-0 lead.
"We walked through the video this morning," Phillip Danault said. "We had some videos together as a line and we wanted to do those little details better, and support each other better as well, which [Gallagher] did on that play. And it ends up being a sick goal by Tomas."
Schenn tied the game 1-1 when he extended his goal streak to four games at 17:57.
Video: STL@MTL: Schenn wires wrister home from the slot
Drouin put the Canadiens up 2-1 at 18:47.
Blais drew St. Louis even for the second time when he scored his third goal at 1:05 of the second to tie it 2-2.
Dunn gave the Blues their first lead, 3-2, when he scored on the power play at 12:50, but Danault tied it 3-3 at 15:35. It was Montreal's seventh tying goal in five games.
Video: STL@MTL: Danault one-times home Tatar's nice feed
They said it
"We couldn't get our forecheck going tonight. That's when we're most dangerous, that's when we sustain zone pressure, that's when the guys get their puck touches in and get their chances in. And whether we didn't dump the puck right or forecheck hard enough, or they just broke the puck out too clean on us tonight, I'm sure it's a combination of everything and we'll be better next game." -- Blues forward Brayden Schenn
"This is a big team that likes to play along the walls, and we had to try and avoid that as much as possible. And I think our guys did a pretty good job between the [defensemen] and the forwards, our centermen coming in with low support, no matter where the puck went. I thought our guys did a pretty good job along the walls when we didn't have a choice and had to rim it. So I think it was more of a five-man unit that was better, but at the same time I think the defensemen were a lot more poised tonight than they had been in previous games." -- Canadiens coach Claude Julien
Need to know
Schenn has 20 points (nine goals, 11 assists) in 22 games against the Canadiens. … Drouin is the third Canadiens player in four seasons to have a five-game point streak to start the season (Alex Galchenyuk, 2016-17; Daniel Carr, 2017-18).
Blues: At the New York Islanders on Monday (Nassau Coliseum; 1 p.m. ET; ESPN+, MSG+, FS-MW, NHL.TV)
Canadiens: Host the Tampa Bay Lightning on Tuesday (7 p.m. ET; NBCSN, TSN2, RDS, NHL.TV)
Video: Canadiens score four unanswered goals to beat Blues