World number one, Rafael Nadal has questioned Andy Murray’s decision to withdraw from this year’s US Open.

30-year-old Murray, who won the US Open in 2012, withdrew from Flushing Meadows last Saturday following his failure to recover from a hip injury he sustained at the Wimbledon.

Speaking after his round one straight-sets victory over Dusan Lajovic, Nadal said: “I always thought that he was going to be playing if he was here practising,”

“It was a little bit strange that he retired just the morning after the draw was made. It was something that is a little bit strange and difficult to understand.”

Andy Murray,  alongside defending champion Stan Wawrinka, Novak Djokovic, Kei Nishikori and Milos Raonic all pulled out of the US Open due to various forms of injury.

“Normally you want to keep practising, keep trying until the last moment. You don’t retire Saturday morning. You retire Monday morning or Sunday afternoon. If not, you can do it before the draw.”

“That’s why I say it’s strange. But of course he has his reason, and for sure the only news, and the negative news, was that he will not be playing here.”

“Injuries are bad for everybody. I know better than all of them. So I wish him fast and good recovery. That’s the most important thing.” the Spaniard added.