Top seed Rafael Nadal advanced into the quarterfinal of the 5.8-million-euro ATP/WTA Madrid Masters in an easy way, as opponent Juan Martin Del Potro withdrew before the match on Thursday.

The Argentina US Open champ Del Potro decided to give up the third-round clash against world No. 1 Nadal due to a hip injury.

Del Potro has been bothered by injuries since he won the US Open in 2009. The Argentinean was out of action for more than eight months after a surgery in his wrist last season.