Andy Murray has revealed that an illness has made the road to another US Open title markedly more treacherous as he prepares to face Thomaz Bellucci on Saturday.

The third seed and 2012 champion, who battled from two sets down to beat Adrian Mannarino in round two, hinted that he has been suffering with a head cold.

The Scot appeared to be wheezing heavily in his arduous win over Mannarino, but Murray says that such obstacles are par for the course of being an athlete.

"I think quite a few of the players have had a head cold," he is quoted as saying by The Scotsman. "My brother was quite sick yesterday, as well. I think there's a few of the players have had it.

"There's no real cure. Hopefully it takes three or four days before it's out the system. The only thing I've taken is Vitamin C – there's not much you can take.

"But that's one of the things about being an athlete – it's survival of the fittest."

The Brazilian beat his Scottish counterpart in the Madrid Masters in 2011 in what remains their only meeting so far.