After Saturday's barracking of Guglielmo Vicario, the away support serenaded the goalkeeper throughout Tuesday night's clash.
Asked about the support of his keeper, Frank said: "You could hear them here, and it's a difficult place to come as away fans and be loud enough so we can hear them.
"So they put so much effort into it, matched the effort from the team and that togetherness drove us forward, and it gave us a more than well-deserved point."
On the spirit shown by his players, Frank also says it was just the tonic after Saturday's home defeat to Fulham.
He added: "Yeah, I think it's hugely important. I think the PSG performance was good. I think the team gave everything against Fulham. It was just a nightmare game in some ways because you're down 2-0 after six minutes, and then keep going and also get something out of it.
"But that's the only way forward, we know that. If you're a tough runner, there's only one way, and that is to work hard and keep going. And the team did that very well today."