I'm gonna quote something I wrote elsewhere earlier today.
I'm not going to discuss the mental fatigue angle because it's unquantifiable, but I do think we, as fans, have a tendency to overstate physical fatigue sometimes when thinking, for instance, "man I hope [Rangers-Hurricanes] goes 7 and the winner wears themselves out". Think about it - the Rangers are pretty much on a game-off-game-off schedule right now, and have been for this entire postseason. Game-off-game-off is more-or-less how the regular season schedule works, and it's the kind of schedule hockey players want. If nothing else, athletes are notorious creatures of habit and Rangers players right now are completely dialed in on their gameday habits and their off day habits.
That's just the way things go. Obviously the Lightning did what they should've done up 3-0 vs. Florida, and that's goes for the kill. You don't play with your food, after all; you don't "throw" a game to try and avoid having an overly-long lay-off between rounds. But I can say that, once I saw that we were playing a Wednesday Game 1 no matter what, that I honestly preferred Carolina end things against New York after Game 6. Not only because I preferred the matchup, but maybe Carolina gets a little bit off after three days of no hockey themselves, either. Because, as it was, we got a matchup between one team that's locked in right now, and one team that was really off their game mentally. I don't think physical rust was a problem, but boy were the details just awful. Nothing close to how utterly locked in they looked against the Panthers.