Mardy Fish has revealed that he could barely make "three or four steps" without suffering from cramp towards the end of his US Open clash with Feliciano Lopez.

The American ended his career with a five-set defeat to the 18th seed at Flushing Meadows, but despite struggling with his movement, the former world number seven has insisted that he never considered withdrawing from his last match.

The 33-year-old told the official ATP Tour website: "I wasn't quitting. I was just cramping. I mean, both sides of both legs, if I moved anywhere close to three or four steps, two or three steps, it would go. You would have had to carry me off the court. I was definitely not stopping at that point."

Lopez moves on to face Milos Raonic in the last 32.