''At the beginning of the third, getting that kill, it gave us such a boost,'' Letang said. ''And then we got a bunch of goals.''
Malkin then scored twice in a span of 2:31 to give him four goals in two games since serving a one-game suspension for a stick-swinging incident.
''He tends to be a guy who builds confidence when he scores, and so I think that bodes well for us and for him,'' Penguins coach Mike Sullivan said. ''He's an elite player ... and you could see it in the third period tonight, the kind of impact he can have.''
Mats Zuccarello had two goals, and Kevin Hayes and Mika Zibanejad scored over the game's final 5:46 for the Rangers, who couldn't complete a second rally after erasing a 3-1 deficit to tie it late in the second period.
Not taking the lead during the four-minute power play that spanned the second intermission was crucial to the game's outcome.
''We got demoralized,'' Rangers coach David Quinn said, ''and they got a new set of energy and a new lift and the whole complexion of the game changed.''
Crosby had three assists to give him 11 points in his past five games for the Penguins, who had won just seven of their previous 17 games to fall in danger of missing the postseason for the first time since 2005-06.
Malkin has points in seven consecutive games that he has played over the past month, interrupted by missing five games with an upper-body injury and the one game because of suspension.
Letang opened the scoring 16:11 into the game. He has 15 goals, one off his career high set in 2015-16.
It was the first time all season the Penguins got four goals from defensemen.
''The last couple games we have been really active getting chances,'' Dumoulin said.
Zuccarello's goals were his 10th and 11th, each tying the game. Ryan Strome also scored for New York, which had won three of its previous five.
The Rangers have scored 11 goals over a two-game span for the first time this season after winning 6-2 at Buffalo on Friday.
Zibanejad added an assist and Chris Kreider had two assists, giving the Rangers' top-line trio of those two and Zuccarello 58 points in their past 14 games.
''Except for those five or six minutes there in the third, I think we played a good game,'' Zuccarello said. ''Obviously, it's a good team over there. They have good forwards. They're going to get some chances, but I think we created a bunch of good chances.
''It could've gone either way. It's hard when they score three right away - boom, boom, boom.''
NOTES: The Rangers scratched D Brady Skjei (lower-body injury sustained during Friday's game), C Brett Howden (MCL sprain) and RW Jesper Fast (flu). Coach David Quinn said Skjei should be able to return for Tuesday's game. ... Rangers D Neal Pionk did not play during the third period as a precaution after he was hit in the eye by a stick. ... Penguins LW Tanner Pearson was a healthy scratch for the second consecutive day after he had been in the lineup for every game since his acquisition from the Los Angeles Kings in November.
Rangers: New York wraps up a four-game trip Tuesday at Carolina.
Penguins: Continuing a stretch of four divisional matchups over a five-game span, the Penguins play at New Jersey on Tuesday.
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