MONTREAL -- Jacob Markstrom had to put in a full 60 minutes to get his second NHL win.
The 21-year-old Swede made his second career start and recorded his second straight win, including an 18-save relief outing in a 4-2 win over the New York Islanders on Saturday.
"For a young guy, it's tough to come into a building like this to start after your first win," Upshall said. "He played unreal in the third period last game for us and to follow it up tonight with save after save, especially late in the game, too. This crowd can be very intimidating but he definitely held himself very well and he was a big part of our victory tonight."
Tomas Fleischmann scored a power-play goal in the first for Florida, which won its second in a row to improve to 5-3.
"The whole team was playing unbelievably well and stuck with it for 60 minutes, and this is the result," said Markstrom, who made 29 saves in a 3-0 loss in Washington in his NHL debut Tuesday.
Montreal fell to 1-5-2, continuing its worst start in 70 years. It is the deepest the Canadiens have gone into a season with only one win since 1941-42, when they got off to a 1-10-1 start that included a pair of losses to the Brooklyn Americans.
"Nobody likes losing," said Erik Cole, who scored on a power play 3:08 in for his first Montreal goal. "We're tired of it. We need to just find a way to get over the hump."
Backup Peter Budaj stopped 29 shots in his Canadiens debut.
"Peter played a good game," Montreal coach Jacques Martin said. "I mean, you can't blame him. He gave us a good chance. He made some big saves at key times in the game."
Upshall deflected Dmitry Kulikov's shot in midair, redirecting the puck past Budaj to give Florida its first lead. A video review upheld the goal.
"I was wondering if they were just doing it to see who scored the goal because the stick was pretty low," Upshall said.
Both teams had new players picked up in trades in their lineups.
Petteri Nokelainen played his first game for the Canadiens, who acquired him in a trade with Phoenix on Sunday.
Cole got his first Montreal goal 3:08 in with a power-play tally that was originally credited to Max Pacioretty. The puck struck Cole in front of the net on its way past Markstrom after Pacioretty deflected Yannick Weber's shot from the point.
Cole, who signed a four-year, $18-million free agent deal with the Canadiens on July 1, drew a cheer for his first goal in eight games when PA announcer Michel Lacroix announced the scoring change early in the second. The goal was only the Canadiens' third in 30 opportunities with the man advantage this season.
Montreal failed to score on two other power plays, including the final 50 seconds after Jason Garrison was called for hooking, falling to 3 for 32 overall.
"To me that was probably the best power play that we've had this year, not only the fact that we scored but we created several other good chances," Martin said. "So I think we've got to continue on that and hopefully we're better on the penalty killing. I think we allowed seven scoring chances tonight and two goals get in."
Fleischmann drew Florida even 1-1 with a power-play goal at 15:59. Kris Versteeg got an assist as Fleischman beat Budaj with a shot that squeaked through the Montreal backup's pads.
Pacioretty left the game after he was injured late in the second. He did not return. Martin said it was an upper-body injury that would be re-evaluated Tuesday.
"At this point in time I don't have any details," Martin said.
Samuelsson got permission from the Panthers to remain in Vancouver. He will remain there for the next few days recovering from abdominal soreness that sidelined him for the Canucks' last two games. ... Florida C Mike Santorelli made his season debut after missing seven games with a shoulder injury. ... Canadiens defenseman P.K. Subban drew a big cheer for his hit that sent Versteeg flying backwards at the end of a Panthers power play in the second. ... Montreal G Carey Price was rested for the first time this season. Price had failed in five straight attempts for his 100th career win since the Canadiens' 5-1 win in Winnipeg on Oct. 9.