The Capitals, boosted by a four-goal third period, including two from recent call-ups Steve Konowalchuk and Keith Jones, edged closer to Patrick Division respectability with a 7-4 victory that extended their unbeaten streak to four.
The Rangers' third-period collapse followed Monday's embarrassing home loss to the expansion Tampa Bay Lightning.
Grumblings about the lack of morale and rumors of trades filled the locker room of the Rangers, who have won only two of their past seven.
The Capitals were talking another tune after their first victory against a division rival in six tries.
"It gets a big monkey off our back," said Jones, who fended off two defensemen to poke a rebound under goaltender Mike Richter to make it 4-4 with 13:53 to play. "We knew coming in we were playing well and this is a huge win. We're going to get on a roll and just keep working."
Konowalchuk would not be outdone by his fellow Oct. 30 call-up, and he got the game-winner with 5:04 left.
Camped on the goal mouth, he took a perfect feed from Paul MacDermid and lifted the puck past Richter.
"Those two kids play big," said Capitals coach Terry Murray. "That is the kind of performances you need from the entire team to win games like this."
Todd Krygier added an insurance goal on a breakaway with 1:52 left for his second goal of the game before Kelly Miller got an open-net score in the last minute.
Backup Jim Hrivnak has been in the nets for the winning revival, replacing the injured Don Beaupre for two victories in the last three games.
This time, though, Hrivnak's winning formula was a little out of the ordinary. After being shredded for three goals on the Rangers' first five shots, he was sat down by Murray.
"I just wanted to break the momentum," Murray said of inserting rookie Byron Dafoe for his NHL debut at 11:10 of the first period. "I wanted to give Hrivnak a chance to catch his breath and told him just one stoppage and he would be back in."
Though he was beaten once more in a frenzied first period, Hrivnak kept the Capitals in the game through the second period and preserved the win with some big stops in the closing minutes.
"It was a pretty good move on his part," Hrivnak said of Murray's strategy. "It gave me some seconds to calm down and get the game back in perspective."
"He's so calm out there," defenseman Calle Johansson said of Hrivnak. "He just stays there and lets the puck come to him. He has been playing great."
The Capitals had closed to 4-3 on Dale Hunter's goal 3:03 into the second period.
The Rangers scored the last three goals of the first period in a closing 10-minute flurry, starting with the second of Darren Turcotte's two goals.
"I thought we had lots of scoring opportunities," Rangers coach Roger Neilson said. "I thought we played with good intensity. But defensively, we have to play a lot better to win games in this league ... We were loose defensively the whole game."
The Rangers must face the reality that with James Patrick sidelined by a sprained shoulder, they are playing with four slow-skating average defensemen: Mark Hardy, Jay Wells, Andersson and Joe Cirella. Leetch, with five goals, is the only defenseman to have scored.
General manager Neil Smith faces a dilemma: How does he improve the defense in a trade without sacrificing one of his young speedy forwards?
The Rangers said working harder would help, but they may not be as good as they were last year. "Obviously," left wing Adam Graves said, "if this was March, we'd be worried. But it's November."
True. But the Rangers are not looking like a team that can compete with the Penguins. Richter disagrees.
"We are a very good team," he said. "We haven't played up to our capacity. That's disturbing. We can use a lot of excuses, but I think all of us have to pick up our game, period."