Although the Canadiens played a solid road game in Ottawa Tuesday night, it all came undone quickly for Montreal in a hurry.
With the Habs holding a 2-0 lead with 8:05 left in regulation - and from tying the series after an emotional fight-filled game Sunday - the left skate of Senators forward Mika Zibanejad changed the complexion of the game - and perhaps the Canadiens' fortunes for this season.
Zibanejad redirected the Chris Neil centering feed past Montreal netminder Carey Price, and gave the Senators - who struggled to build momentum up to that point in the contest - a huge boost in front of the sellout crowd at Scotiabank Place.
The Senators outshot the Canadiens 13-4 in the third, and eventually were able to take advantage of a pair of late Montreal icings to keep pressure on Price.
With Craig Anderson -- who kept the Senators within striking distance -- pulled for an extra attacker, Cory Conacher, acquired in a trade from Tampa Bay earlier this season, forced overtime by moving into empty space in front of the Montreal cage with just 22.5 seconds left and depositing the puck past Price.
Things got worse for Montreal, as they lost Price to injury.
After making a save in the dying seconds of regulation, Price suffered what was termed a lower-body injury and didn't come back out for overtime. Backup Peter Budaj came in cold, and lasted 2:32 before Kyle Turris ended the contest and dropped Montreal into a 3-1 hole in the series after alate collapse where everything that could go wrong for the Habs did.
After the improbable season that saw the Canadiens return to the playoffs by winning the Northeast Division, the Habs will need another improbable scenario to keep their season going past the weekend.
Anderson has been the equalizer for Ottawa, playing fantastic hockey at times, and keeping the Sens from falling too far behind in games. Anderson has faced 138 shots, most of any goaltender in the playoffs, yet has a .945 save percentage and just a 2.00 goals-against average.
For their part, the Senators have been the apparent team of destiny this season, managing to make the playoffs despite losing both Jason Spezza and Erik Karlsson for most of the season. Now, with the team getting healthier and Karlsson back in the lineup, as well as Anderson playing well, the Canadiens will have a big task in front of them.
Even Conacher and Senators coach Paul MacLean acknowledged that they seemed to have a bit of good fortune Tuesday, and certainly it seems the breaks are going Ottawa's way at the moment.
In hockey-mad Montreal, there is no room in the rafters at Bell Centre for division, conference or other title banners, simply Stanley Cup championships. But with the last one coming in 1993 - the longest the Canadiens have gone without a Cup since the club's first before the National Hockey League was even founded - the locals are running out of patience.
Should Price be unable to play in Game 5, it will be up to Budaj to try and turn the series around, and certainly will need to deliver some big saves as Anderson has given Ottawa.
Montreal will also need to find a way to beat Anderson, generating traffic in front of the Ottawa net and scoring the kind of goals that the Senators used to steal Game 4 from the Habs. For a team that has struggled at times to light the lamp this year, that won't be an easy task.
For now, the seventh-seeded Senators are wearing hockey's glass slipper, and getting a chance to knock off its closest rival with a rather improbable performance.