Tomas Berdych has admitted that it would be "tough" for him to break into the top four of the world rankings.
The Czech Republic number one is currently ranked seventh in the latest standings.
"Of course, [Federer and Nadal] already know they are two in the semis. We will see what's gonna happen tomorrow," he told reporters.
"This is probably the toughest time to play because of those four really strong guys. They are making history every week they go and play.
"So, it's tough, but it's how it is. We just needs to deal with it."
Berdych has never gone beyond the last eight in Melbourne.