Hart was pulled during a timeout with 11:16 left in the second. He has allowed 12 goals on 43 shots over his past three starts.
"You've just got to find a way right now, and for me, I just have to find a way to get back into my old rhythm," Hart said. "Right now, I'm just not playing where I feel I should be at, and I know I'm better than that. I just have to keep working.
"I've been feeling really good in practice, but I think right now, just go out into the game and just play. I think I may be overthinking a couple of things, but I've just got to go out and play. Just play the game."
Giroux scored at 17:04 of the third period for the 5-3 final.