The Eagles have it all to do in the Ashton Gate return, but Warnock has faith that his players can turn the tie around.
He commented: "I was disappointed in the manner that we conceded the goal at the death, but the goal was fit for any Premier League game never mind the play-offs.
"I think you could see from their celebrations that they were already at Wembley. I didn't think much of their celebrations to be honest.
"There was no need to go off like they did. They are 2-1 up, but I think celebrations should be kept until you are through, because football has a habit of getting you back."