Mardy Fish withdraws from US Open

American Mardy Fish has been forced to pull out of the US Open for health reasons.

The 30-year-old had been due to take on world number one Roger Federer in round four later today.

However, a so-far unspecified medical complaint has forced the world number 25 to withdraw at short notice.

As a result, Federer has now qualified for his 34th consecutive quarter-final at a Grand Slam event.

He will now face either Tomas Berdych or Nicolas Almagro for a place in the semis.