Roger Federer into US Open last eight after Mardy Fish pulls out

World number one Roger Federer made the US Open quarter-finals without hitting a ball after opponent Mardy Fish withdrew because of health reasons.

Five-time champion Federer will face Czech sixth seed Tomas Berdych for a place in the semi-finals.

Berdych beat Spaniard Nicolas Almagro 7-6 (7-4) 6-4 6-1.

Later on Monday, Britain's third seed Andy Murray plays 15th seed Milos Raonic, while 12th seed Marin Cilic plays Martin Klizan.

Fish missed about two months earlier this season because of an accelerated heartbeat and had a medical procedure in May.

The 30-year-old American's third-round match against Gilles Simon went five sets, lasting more than three hours and finishing after 1am on Sunday.

Fish's agent, John Tobias, said: "We are not 100% sure what the issue is and if it is related to his previous issues."

"I was reluctant to do so [withdraw] but am following medical advisement," said Fish in a statement.

"I had a good summer and look forward to resuming my tournament schedule in the fall."

Source: British Broadcasting Corporation