When all four second-round series in the NHL playoffs tilted 3-1 through four games, players and coaches didn’t have to look far for examples of teams that have come back from that deficit — or let that lead slip away.

Boston goaltender Jaroslav Halak backstopped Montreal to a seven-game victory against Presidents’ Trophy-winning Washington in 2010. Philadelphia coach Alain Vigneault was behind the bench for two of them, with Flyers defenseman Matt Niskanen on the other side in 2014 and 2015 and the second against now-New York Islanders coach Barry Trotz. Peter DeBoer led the San Jose Sharks back from down 3-1 a year ago against the Vegas Golden Knights team he’s now coaching.

“Everyone’s played in these types of games throughout their life,” said Chris Tanev of the Vancouver Canucks, who in Tyler Toffoli and Tanner Pearson have players who were part of a 3-0 series comeback. “Maybe not in the NHL for everyone, but guys have played at high levels their whole life and they’ve faced elimination before.”

Just not while competing for the Stanley Cup in a quarantined bubble. Bruins coach Bruce Cassidy predicted three weeks ago that series would end quicker because of the psychological element of players being isolated from their families and their lives back home.

It is a variable unlike anything before in hockey history that makes the climb back from being down 3-1 even steeper.

“For sure, this is new for everyone,” Vigneault said ahead of his team’s Game 5 Tuesday against New York (7 p.m. EDT, NBC Sports Network). “Obviously this is a totally different environment, but the focus needs to be the same. It has to be on that one game.”

While a 3-1 comeback has happened 29 times before in an NHL best-of-seven series, only one team facing that deficit in the first round even forced a Game 6: the Canadiens against the Flyers.

If none of these series go the distance, it will mark the first time since 1979 that the Stanley Cup playoffs didn’t have at least one Game 7 in the first two rounds. That was the year before the league absorbed teams from the World Hockey Association and Wayne Gretzky made his debut, and the first round was best-of-three.

Now 41 years later, not only does the sport look different, but games are being played without fans in Toronto and Edmonton. The time-honored approach to mounting a comeback remains the same.

“We’ve just got to win one game,” said coach Travis Green, who guaranteed his Canucks would be ready to go in Game 5 (9:45 p.m., NBCSN). “We’re not looking at it like this is Game 7. We’ve just got to win one game.”