Their heart and their resilience.
The win evened the best-of-seven Patrick Division finals at 2-2 with Game 5 to be played at Madison Square Garden tonight.
Francis completed a hat trick when he redirected a shot by defenseman Larry Murphy through goalie John Vanbiesbrouck after Murphy stole the puck from Mark Messier.
"One individual can't replace Mario Lemieux, he means too much to this hockey team," said Francis, who took Lemieux's spot in Pittsburgh's top line. "It's not just me replacing Mario, it's a bunch of guys. When we got down two goals, we knew we had come back because we couldn't afford to go back there down 3-1 in the series."
The Penguins' Kevin Stevens said: "Even I don't know how we do it sometimes. What Ronnie Francis is doing is unbelievable. He knows Mario is out and he's turned it up to another level."
The Penguins came from two goals behind during an inspired third period.
After Messier scored his second goal of the game to make it 4-2 in the third period, the Rangers went on a five-minute power play when Penguins defenseman Gordie Roberts drew a major for cross-checking.
Pittsburgh should have had enough by then.
Yet, the Penguins killed the penalty and were resuscitated when Francis and Troy Loney scored goals just 1:25 apart to tie the game and send their fans into a frenzy.
"Scoring after killing the penalty was huge," Francis said. "If they would have gone ahead 5-2, they would have buried us."
Mike Richter was replaced by Vanbiesbrouck in the Rangers' net after Loney's goal.
As they did in their 6-5 overtime loss Thursday night, the Penguins started slowly and twice fell behind by two goals.
And with no Lemieux to provide the booster for a catch-up game, the Pens were clearly taking the wrong approach.
But a power-play goal by Ron Francis with only six seconds remaining in the second period brought Pittsburgh to within 3-2 and kept its pulse beating.