They dove in front of pucks, they jumped up to swarm rushes, they stepped in to close off passing lanes, and where they failed, their magnificent netminder bailed them out.
The Canadiens' Benoit Pouliot, not known for his defensive zeal, slid out to stifle a shot in the slot with his team hanging grimly on to a 1-0 lead.
Defenceman Josh Gorges made a deft stick move to snuff out a golden scoring chance late in the third.
They blocked 41 shots in all, fuelling the growing legend that is Jaroslav Halak in a famous 2-1 victory that must rank as one of the more shocking upsets in recent hockey history.
"Even before the series started, no one gave us a chance to win even one game . . . we showed a lot of character after being down 3-to-1 [in games]" said Halak, who has parried an otherworldly 131 of 134 shots in his past three games.
Anyone looking at why the Washington Capitals came up short despite having a 3-1 lead - the seventh time the franchise has frittered away a two-game bulge in the past three decades - need simply look at the respective teams' penalty killing.
With his team in dire need of a goal, the Caps' mercurial Alexander Semin had the chance to jump on a loose puck in the neutral zone, but let up.
At the other end, Montreal's Dominic Moore, author of the winning goal, was taking a puck in the face and nevertheless continuing to hound Caps.
"I guess it's part of the portrait of the playoffs, a little blood in the beard," said an elated Moore, sporting an angry welt on his chin. "Just to be able to play in this game was special, but to win . . ."
Fittingly, the Caps' season ended on the power play, their meat and drink all year, but when they needed a goal most - Brooks Laich had made the game 2-1 with 2:16 to play and the Verizon Center was in full froth - none was forthcoming.
They ended the series an abysmal 1-for-33 with the extra man.
Part of that was surely the result of the visitors playing a near-perfect road game and held superstar Alexander Ovechkin in check for most of the night.
And in a playoffs that has featured plenty of grumbling over officiating decisions, the conspiracy theorists will nod knowingly and point to a disallowed Ovechkin goal early in the third period for goalie interference.
A Capitals spokesman tweeted during the game that "no way that call is made if 87 scores," referring to the Pittsburgh Penguins' Sidney Crosby - whose team awaits the Habs tomorrow night.
But the plain fact is the Capitals have no one to blame for themselves, and the Canadiens should be given ample credit.
Defenceman Mike Green will likely wear the goat horns for taking a foolish penalty that allowed the Canadiens to take a late first-period lead on Marc-André Bergeron's power-play goal, but there is plenty of blame to go around.
Semin, who had no goals and just two assists, Ovechkin, who was unable to find a way around the Montreal defence, are just two who will face uncomfortable questions.
"With the offensive capabilities we have . . . this is really disappointing and frustrating," said Washington's Mike Knuble.
The Caps scored 17 goals in games two through four, but only four over the final three.
Halak continued to mesmerize Washington's shooters, and though he wasn't called upon to do the impossible as he was in game six, was efficient and composed.
The Canadiens' victory marks the second time in franchise history they have erased a 3-1 series disadvantage, and it also marks the first time under the playoff format adopted in 1994 that an eighth-seeded team has upset a top seed that held a 3-1 series advantage.
So the Habs follow on the heels of eighth seeds like the Edmonton Oilers, who stunned the heavily favoured Detroit in 2006, and the Anaheim Ducks, who turned the same trick on San Jose last season.