11:24PM BST 19 Aug 2011
American seventh seed Mardy Fish defeated second seed Nadal 6-3, 6-4 while eighth-seeded Czech Tomas Berdych dispatched world No 3 Federer 6-2, 7-6 (7/3).
Berdych claimed a third victory over Federer in their last three meetings, taking full advantage of the Swiss star's struggles with his groundstrokes.
Berdych will next face the winner of the remaining quarter-final between world number one Novak Djokovic and sixth-seeded Gael Monfils of France.
Fish, who zinged a cross court forehand past Nadal on match point to seal his first victory over the Spaniard in seven attempts, next faces world number four Andy Murray, who cruised past France's Gilles Simon 6-3, 6-3.
Nadal had battled through three tiebreakers over three and a half hours to beat Fernando Verdasco a day earlier.