Should the rain stay away, then England could bat for as many as 98 overs as they look to retain the Ashes, but Prior is not fazed by that possibility.
"The one thing about this England team is that we have become tough to beat," Prior told BBC Sport. "We've been in this position a few times in the recent past. We'll have a lot of confidence going into tomorrow that we can save the Test.
"It's a good batting wicket - there is the odd ball that bounces and turns but you'd expect that from a good Test pitch on the fifth day.
"The key will be getting through the new ball. When the ball gets softer it will still spin, but not as quickly, and it becomes harder work for the seamers as well."
England require a draw to retain the Ashes.