A set down and facing set point in the second, Nadal dug himself out of a cavernous hole to overhaul the tall Czech in a taxing four-hour tussle under the lights at a frenzied Rod Laver Arena.
Dashing from corner to corner in a lime-green shirt, 2009 champion Nadal met seventh seed Berdych's power game with his own brute force and picked him off repeatedly when he charged cavalier-like to the net.
The pressure told and Berdych surrendered a decisive break in the opening game of the fourth set and another when serving to stay in the match to allow the world number two to keep his bid for an 11th grand slam crown alive.
Image: Rafael Nadal of Spain celebrates after defeating Tomas Berdych of the Czech Republic during their quarterfinal at the Australian Open tennis championship, in Melbourne, Australia, Tuesday, Jan. 24, 2012.
Australian Open 2012