Nadal collapses in press conference

US Open champion Rafael Nadal dramatically collapsed during his press conference this afternoon after beating David Nalbandian to advance to the fourth round.

There did not appear to be anything wrong as he answered questions in English but after he had begun to talk to journalists in Spanish he clearly began to feel pain and called for the trainer before sliding off his chair and onto the floor.

Nadal lay on the floor behind the desk of the interview room at Flushing Meadows for several minutes before getting up and walking gingerly out of the door.

The 25-year-old then returned and was quick to allay any fears about his health, revealing he had been suffering from cramp in the front and back of his thigh.

He then resumed his press conference.