It was in 2011, and the Boston Bruins stormed back to win on a Nathan Horton shot off a defenceman's leg in Game 7 overtime.
Before that was 2006, when the Canadiens took the opening two games in Carolina only to drop the next four, partly through losing star centre Saku Koivu to a series-ending eye injury from an accidental high stick by Justin Williams in Game 4.
Both times, the team that came back to beat the Canadiens went on to win the Stanley Cup.
After taking their opening two games of this year's playoffs with wins of 5-4 and 4-1 over the Lightning in Tampa, Fla., Gionta doesn't want history to repeat itself.
"It's huge, but at the end of the day, we fell into that trap against Boston a few years back," the Canadiens captain said Saturday. "We won two games in their building and we came back and let off the gas a bit.
"So we need to make sure that our focus is on (Sunday) night and make sure we do what we did in the first two games."
Game 3 of the best-of-seven series is set for Sunday night at the Bell Centre, where a wall of sound from the 21,273 spectators is expected to greet the Canadiens.
They didn't skate after a late-night flight home from Tampa, but the message from the coach Michel Therrien and his staff was about taking care of business on home ice.
"We all understand that the farther you get in the playoffs the more difficult the games are to play," said Therrien. "We're glad we're back at home, but I like our focus.
"We have a business mentality. It's about preparing ourselves for (the next game)."
Therrien has much to be pleased about.
His team has had the edge on the Lightning for all but the first period of Game 2 on Saturday night, when strong goaltending from Carey Price kept the game scoreless until Montreal took control in the second frame on a power-play goal from David Desharnais and Rene Bourque's first of the game.
Brendan Gallagher and Bourque added goals in the third before Teddy Purcell got one — on a power play plus the goalie pulled for an extra attacker — at 18:01.
The Desharnais goal broke a nine-game drought for the Montreal power play.
They have also been getting scoring from all four lines. Eight different forwards have scored goals, which takes some pressure off the top unit of Desharnais, Max Pacioretty and Thomas Vanek.
Desharnais got his first goal in 12 career post-season games, while Pacioretty's assist on the same tally was his first point in six career playoff games. The line combined for 22 shots in two games, so it should produce more as the playoffs go on.
The Canadiens also took advantage of the absence of Tampa Bay's injured top goalie Ben Bishop by beating Anders Lindback eight times in two games and adding another against Kristers Gudlevskis — the Latvian who made 55 stops in a 2-1 loss to Canada at the Sochi Olympics. Gudlevskis let in one goal on three Montreal shots.
And they held Tampa Bay star Steven Stamkos to two goals, both in Game 1, and no assists, although the gifted sniper has nine shots on goal.
So the Canadiens are in good position to win a playoff series for the first time since goalie Jaroslav Halak's heroics got them to the Eastern Conference final in 2010.
But they know how far away that goal is.
All-time, the Canadiens are 49-5 when leading a best-of-seven series 2-0, but have lost three of the last four times in that situation.
"They're going to make adjustments," said Gionta. "It's the playoffs and you've got to try to read what they're going to do, make adjustments on the fly, and see what happens.
"I thought we did a fairly good job of that (Friday) night. We need to do it again."
Gionta's line with centre Lars Eller and left-winger Bourque has been particularly solid. Eller entered this year's post-season with two assists in eight career games, but now leads the team with a goal and two assists.
Bourque was a target for fans all through a sub-par regular season with nine goals in 63 games in which he was made a healthy scratch for the first time in his career. He sat out five straight games in March.
He may get a warmer reception after two solid games in Tampa, including his first career playoff game with more than one goal.
"Since he's back in our lineup, before the playoffs, Rene Bourque was playing the way we expect him to play," said Therrien. "We don't judge players only on goals and assists.
"What I like is that he's engaged in the game. He's physical. He's going hard to the net and he got rewarded."