TORONTO -- Carey Price had played two periods of hockey -- in the minors -- over the past month coming into Thursday.
Paul Byron, meanwhile, found himself on waivers three separate times this season, his future with Montreal very much hanging in the balance.
Combined with their teammates' gritty top-to-bottom performance, the duo helped the underdog Canadiens fire a surprising opening playoff salvo in this much-anticipated battle of Original Six rivals.
Byron scored the short-handed winner from his knees with under eight minutes left in regulation and Price made 35 saves as the Canadiens defeated the Toronto Maple Leafs 2-1 to take a 1-0 lead in their first-round series.
Montreal limped into the playoffs, both on the ice and with a rash of injuries, but now has the upper hand after finishing 18 points back of first-place Toronto in the NHL's one-off Canadian-based North Division during the pandemic-shortened regular season.
"New ball game now," said Price, who was sidelined with a concussion. "We had struggles through the season, but got to the playoffs.
"It's a new season."
Josh Anderson had the other goal for Montreal, which will look to repeat the feat in Game 2 back at Scotiabank Arena on Saturday in the teams' first post-season matchup since 1979.
William Nylander replied for the Leafs, who got 28 stops from Jack Campbell in his playoff debut.
With Tomas Tatar in the penalty box for high-sticking and the Leafs looking to take the lead, Byron raced passed rookie defenceman Rasmus Sandin, who tried to drag down the Montreal forward, before roofing a shot upstairs on Campbell with 7:46 remaining in the third period.
"Feisty player," Price said of Byron. "He's a finisher."
A physical, intense start to proceedings was brought to a standstill midway through the first when Leafs captain John Tavares was involved in a scary collision and had to be stretchered off the ice.
"He's conscious and communicating well," Toronto head coach Sheldon Keefe said. "The tests he's had so far have come back clear. He's going to remain in hospital overnight to undergo further tests.
"It's a big loss for us, but we've got lots of depth. Good teams overcome these types of things. That's going to be on us."
The Canadiens got a boost with the return of Price, captain Shea Weber (upper-body injury) and Brendan Gallagher (broken thumb). The Leafs, meanwhile, had defenceman Zach Bogosian (upper-body injury) back in the lineup, while centre Riley Nash (knee) made his Toronto debut after being acquired prior to the trade deadline.
Tavares was injured at 10:29 of the first after taking an initial hit from Canadiens defenceman Ben Chiarot in the neutral zone that felled the veteran forward before he took an accidental knee to the face from onrushing Montreal winger Corey Perry.
"Felt sick to my stomach," said Perry, who has played with Tavares internationally for Canada. "Scary situation."
Trainers and doctors from both teams rushed to attend to the 30-year-old, encouraging him to stay on the ice as he struggled to get up. Tavares offered a thumbs up as he was stretchered off inside an empty and silent Scotiabank Arena.
"I've experienced a lot of different things, a lot of tough injuries like that in my time," Keefe said. "In an empty building like that, it's probably the most uncomfortable situation I've been a part of on the ice. It was really tough to get through.
"Our players were rattled and concerned. I was obviously very concerned."
Although the injury was unintentional, Perry dropped the gloves with Leafs winger Nick Foligno as soon as play resumed.
"Our captain's laying on the ice," Foligno said of why he asked Perry to fight. "It's nothing more than that. Perry obliged.
"It just addresses the situation and everyone moves on."
Montreal pushed the shock of the injury aside fastest and grabbed the lead at 12:08 when Anderson split Bogosian and Sandin before moving in alone and firing in off Campbell's post.
"There's a lot on the line," Anderson said. "Best time of the year."
Without a playoff series win since 2004, the Leafs ended the period on a power play, but Price was bailed out by one of his posts on a shot by NHL goal leader Auston Matthews.
Toronto, which had defenceman Jake Muzzin stretchered off in last summer's post-season bubble, tied it up at 4:28 of the second on a sequence that started with a terrific Foligno forecheck. Morgan Rielly's point shot hit a body in front and fell to Nylander, who slid his shot past Price.
Nylander had a great chance to put the home side in front on another power play later in the period, but could only find iron.
Campbell, who got the start ahead of Frederik Andersen following a record-breaking campaign, then denied Tyler Toffoli with his glove on another man advantage.
Rielly blocked an Anderson chance early in the third with Campbell out of position before the Leafs killed off a Mitch Marner penalty for delay of game.
Nylander took another delay of game penalty -- Toronto's third of the night -- a couple of minutes later, but the Leafs managed to once again survive. Marner was then robbed by Price's blocker with the netminder at full stretch on a 2-on-1 with Nylander before Byron buried the winner.
Toronto got a power play with 3:18 left, but Price stopped Nylander from the slot and Zach Hyman from in close with Campbell on the bench for an extra attacker before the visitors closed it out despite more pressure at 6 on 5.
The vibe outside Scotiabank Arena was nothing like the leadup to a normal playoff series -- especially between two legacy organizations -- as COVID-19 restrictions continue to keep fans in Canada from attending in person.
Maple Leaf Square, normally a gathering spot for rabid crowds to watch games on a massive outdoor screen, had just a few jersey-clad fans milling about a couple of hours before puck drop.
Teams in the U.S. have all had some spectators at their playoffs games, and the Canadiens have been given the green light by Quebec's government to allow 2,500 fans into the Bell Centre for Game 6 if the series goes that far.
Thursday's tilt was the first in the post-season between the teams in 42 years, and opened just the third head-to-head series since the NHL started to expand back in 1967 after Toronto beat Montreal to secure the franchise's last Stanley Cup.