Tomas Berdych has praised the impact of coach Dani Vallverdu after breezing through to the last eight of the Australian Open.

The seventh seed hasn't dropped a set during his opening four matches, and ahead of his showdown with Rafael Nadal on Tuesday, the Czech player has revealed that linking up with Vallverdu has given him an extra edge in Melbourne.

The 29-year-old told reporters: "He knows how to put up the plan before the match and how to prepare the player. He is very good at that.

"That's the positive that I was looking for and what I needed."

Vallverdu had previously worked with long-time friend Andy Murray before they parted ways at the end of last season.