Though he didn't even win a single point in his fourth-round match at Flushing Meadows, top seed Roger Federer advanced into the field of 16 anyway on Labor Day after his opponent Mardy Fish withdrew from contention.

Fish, the No. 23 seed in the men's draw, reported 'health reasons' on Monday afternoon after suffering heart problems shortly following his grueling third-round victory over Gilles Simon. Fish has been forced to deal with a number of heart-related issues before in his career and clearly did not want to take any chances after such a serious scare.

Federer's opponent in the quarterfinals, No. 6 seed Tomas Berdych needed just three sets to dispose of No. 11 seed Nicolas Almagro (7-6 (7-4), 6-4, 6-1) on Monday to keep his impressive tournament going. Berdych's fourth-round victory gave the Czech Republic native his first career quarterfinal appearance at a U.S. Open, even though it's clear he will have his hands full with a fully-rested Federer if he has any hopes of reaching the final four.

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