The Penguins outshot the Rangers 23-8 in the second period.
"Great game by two teams," New York coach Gerard Gallant said. "Thought the first 25 minutes we were real good, dominated that part of the game and then they come back in the second and they played really well after that. It was one of those games, three overtime periods, it's tough to lose like that, but you get back on the horse and get ready for the next game."
Domingue, who got his first NHL playoff win, played two games for the Penguins during the regular season, when he was the third-string goalie behind DeSmith and Tristan Jarry, who is out with a lower-body injury. It was Domingue's second playoff game; he made seven saves in relief for the Tampa Bay Lightning during a 4-2 loss to the Washington Capitals in Game 1 of the Eastern Conference Final on May 7, 2018.
"It's something you prepare for as a backup," Domingue said. "You have to be ready at all times, and the guys played super well in front of me for the time I was in there and I thought Casey gave us a [heck] of a chance to win that game or put us in a position to actually go to overtime."
The Penguins also played without forward Rickard Rakell (undisclosed) for the final five periods after he left the game following a hit by Rangers defenseman Ryan Lindgren late in the first.
"It's a character win," Pittsburgh coach Mike Sullivan said. "I just think so highly of our players and our leadership. I just think believe these guys are capable of so much and we have a high-character group, and I think that was on display on a game like tonight."
NOTES: Joonas Korpisalo made 85 saves for the Columbus Blue Jackets against the Lightning in Game 1 of the 2020 first round, won by the Lightning 3-2 in the fifth overtime. … Crosby has 124 playoff assists, tied with Sergei Fedorov for eighth in NHL history. … Penguins defenseman Kris Letang played a game-high 46:41. Fox and fellow defenseman K'Andre Miller each played a Rangers-high 44:28. … New York has won 10 of 39 best-of-7 series when losing Game 1; Pittsburgh has won 23 of 31 such series when winning Game 1.