Sitting in the sixth tier of the football pyramid, Macclesfield made history with this 2-1 win, the gap between themselves and Palace the greatest in a FA Cup win.
Rooney said afterwards, "I can't believe it, we never thought we would be in this position.
"We were incredible from the first minute. I thought we were deserved winners. I couldn't be any prouder of the lads.
"I couldn't have asked any more of them and you can see the joy in them."
On skipper Paul Dawson, Rooney added: "Dawson is one of them, he is unbelievable in the air. He scores goals from the field and can play centre half, he puts his head where his goals are. He has that passion and sometimes we have to rein him in a bit but he was incredible today. He is a class clown.
"I didn't think it was possible but there is that little bit of hope that anything can happen on the day."