Nadal, Djokovic threaten to boycott next Madrid tennis Masters

Rafael Nadal has exited the Madrid tennis Masters - possibly for the last time.

Roger Federer has eased into the quarter-finals in straight sets, while Serena Williams has come from a set down to beat Caroline Wozniacki.

he world tennis number two says he won't play the event next year if the blue, slippery clay court remains the same.

Beaten in three sets by Fernando Verdasco, Nadal's unsure whether other senior players would echo his threat to boycott next year.

But he says people in positions of power have made poor choices.

Nadal says the tournament is great but it's a bad decision.

Roger Federer says he can understand why Nadal is so angry, as he's been against the surface from the start.

"So obviously for him to go out, for him it's the second round, but it's the third round, is obviously disappointing, but we never felt comfortable on the surface, it is a tough surface. Obviously that only ignites the anger even more."

Roger Federer has safely advanced to the quarter-finals along with world number one Novak Djokovic.

Djokovic has echoed Rafael Nadal's threat to boycott the Madrid Masters unless it gets rid of the blue clay.

The world number one has avoided Nadal's fate and moved through to the quarter-finals of the top tier tournament, but remains outspoken in his criticism of the surface.

Djokovic fears a serious injury, due to the slippery conditions.

"Especially for somebody that slides a lot like Rafa (Nadal), myself, (Gael) Monfils, we have different footwork from some other players. We need to slide and that's how we've played all our lives."

He says organisers are claiming the blue clay is the same as the red clay, but it's simply not true.