Rafael Nadal threatened to boycott next year's Mutua Madrid Open if the competition continued to use a blue colored clay playing surface.

Nadal was speaking after his 6-3, 3-6, 7-5 defeat to Fernando Verdasco in the last 16 of the competition on Thursday afternoon.

The No. 2 seed had appeared to be on course for victory as he led 4-1 in the final set, but Verdasco broke his serve four times in succession to win the game.

Nadal had been critical of the decision to play the tournament on blue clay, the first time beaten clay has ever been colored anything other than the traditional red in Europe and after congratulating Verdasco for his triumph, he dropped his bombshell, clearly annoyed at the slippery playing surface.

"I did my best. I came here on Thursday to prepare, but I wasn' t good enough to adapt to this court. I am sad, but next year it will be one less tournament on my calendar," he said in a clear challenge to the tournament organizers.

"I don't know how many other players feel this way. This is a great tournament, but it is a bad decision and you can either change or keep a bad decision," continued Nadal, who added that he was not speaking in the heat of the moment.

"I know what I am saying. I always like playing in Madrid and I try to do as well as possible and that is why I got here early. This surface is totally different to what we are used to. I don't want to risk injury to my hip, it hurts because I continually had to correct myself on court and I will not take risks with my health, so I would rather not come," he continued.

"You can't balance, you can't support yourself and you fall forward when you serve. Support, control and mobility are key in tennis and you can't do that here," said Nadal.

Earlier in the day Serena Williams had commented that the blue clay was like a "skating rink," adding that fortunately she was good at skating.

Meanwhile Novak Djokovic had shown his displeasure earlier in the week, commenting that he was considering playing in football boots to help him keep his feet.