Let's be clear, though. Disrespecting an opponent that for 40 minutes looked overmatched, and getting one point out of a game they should have gotten two, isn't the be-all, end-all of the Penguins' season.
If anything, it's human nature that something like that happens, because the Penguins know they're going to make the playoffs and know the opportunity to "Three-peat" is real.
However, if analyzed properly, what happened at the Garden, especially juxtaposed against what happened in the third period of their 3-1 win against the Dallas Stars at PPG Paints Arena on Sunday, should turn into teaching points for Sullivan.
Pittsburgh played arguably its best third period of the season against the Stars. The Penguins preserved a 2-1 lead by limiting Dallas to four shots on goal, one in the final 10 minutes, and 11 total shot attempts before Evgeni Malkin sealed the win with an empty-net goal at 19:16.
"Against Dallas, everyone bought in in the third," Hagelin said. "We got pucks out. We didn't give them any chances because we were playing hard, playing smart."
The opposite happened against the Rangers.
"We were swinging away from pucks and we were not winning battles," Hagelin said. "The Rangers did a good job of creating chances off our mistakes."
Pittsburgh allowed New York 17 shots on goal and 23 total shot attempts in the final 22:53, including overtime. The Penguins had seven giveaways in the third period. They committed two penalties and the Rangers scored on both.
"We totally ruined it," Letang said.
Hagelin said the Penguins were lucky to even get a point with the way they played in the third, by trying to make the hard play instead of just chipping the puck out and forcing the Rangers to retreat and try to come 200 feet to score.
"We stopped playing," he said. "We're not a tough team to play against if we're not doing everything the right way. You could see that. They came in waves. They kept creating chances after chances. We just looked flat.
"I'm hoping that's a wakeup call for us."