The loss also marked the first time in Montreal's gloried 102-year franchise history that the Canadiens have failed to win a single one of their first five home games.
But for the current group in the Canadiens' dressing room, history is of little interest. It is the present and future that are front and center in their minds.
"We're not happy, that's for sure," said center Tomas Plekanec. "We have to be better. Our group has more, and we know that. We just have to bring it."
Markstrom – who was originally drafted by Canadiens coach Jacques Martin when he was GM in Florida – was outstanding all night long, but never more so than when he dove across to stop a shot batted out of the air by Michael Cammalleri, and then was able to get back to stop Mathieu Darche on the rebound late in the first period.
Upshall said the Panthers sometimes wonder about what species the 6-foot-6 Markstrom is, or if he is even of this Earth.
"He's like a Transformer," Upshall said. "We're not sure if he's human or if he's part alien."
As if losing the game wasn’t bad enough for the Canadiens (1-5-2), they also lost the services of leading scorer Max Pacioretty who appeared to hurt his shoulder chasing a loose puck late in the second period.
"There's urgency, and I think the players understand that, their effort tonight showed that they do," Martin said. "It's not a question of urgency, it's a question of certain mistakes, certain moments that cost us. Our group has been in the League long enough. That's why it’s disappointing to lose games that we have to win, but we just need to correct certain aspects and continue working."
The Panthers (5-3-0), meanwhile, continued their strong start to the season with a brand new team, winning their second straight after a two-game losing streak last week where they were shutout in back-to-back games.
"Tonight was a pretty good example of how we win games," Panthers rookie coach Kevin Dineen said. "We have good goaltending, our defense plays extremely hard and we need all our forwards. We need that depth to play the way we play."
The Canadiens also got a strong performance from backup Peter Budaj in his first start in a Canadiens uniform with 29 saves.
"We allowed seven scoring chances tonight and two goals got in," Martin said. "Peter played a good game. You can't blame him. He gave us a good chance. He made some key saves."
It was a night of other firsts in Montreal. Newly-acquired Marco Sturm played his first game for the Panthers, while Petteri Nokelainen did the same for the Canadiens. The same was true of Michael Blunden, who was called up from the AHL and flanked Nokelainen on the fourth line.
Upshall's game-winner was his first in a Panthers uniform after signing with them as a free agent, and the same thing happened to Erik Cole for the Canadiens.
Montreal's big-ticket free agent acquisition had been a minor source of controversy despite himself of late, with the media questioning Martin's usage of him. It came to a head Saturday night, when Martin had a testy response to a reporter's question of why Cole wasn't on the Habs struggling power play.
Coincidentally or not, Cole found himself on the power play Monday and promptly scored, though the goal was originally given to Pacioretty.
Cole, however, insists that he never touched the puck, and under the grim circumstances he doesn't much care either way.
"I didn't realize that was my goal. I'm sure they'll take another look at it, but I'm pretty sure that went off Patch's stick," Cole said. "I guess it doesn't really matter. The result's still the same."
The teams played to a draw for 40 minutes, with each scoring on the power play in the first period. Cole opened the scoring at 3:08 of the first, tipping a Raphael Diaz shot that had already been deflected by Pacioretty in the high slot.
Tomas Fleischmann tied it for Florida at 15:59 when his shot from the goalmouth trickled through Budaj’s pads for his second goal of the season.
Upshall got the winner on a deflection of a point shot from Dmitry Kulikov – who was a force all night – at 5:02 of the third.
Markstrom did the rest, most notably keeping the Canadiens off the board with three saves while they enjoyed a 6-on-4 advantage for the final 49.9 of regulation.
"He just made save after save, especially late in the game," Upshall said. "This crowd can be pretty intimidating, but he definitely held himself very well and was a big part of our victory tonight."
He played an equally large role in greatly complicating the life of the general manager who drafted him.