Rafael Nadal, who has been one of the most vocal critics of Madrid's new blue clay courts

Rafael Nadal, who has been one of the most vocal critics of Madrid\'s new blue clay courts Rafael Nadal threatened to skip next year\'s Madrid Open on account of its controversial blue clay surface after he blew a 5-2 final-set lead to exit this year\'s tournament to Spanish compatriot Fernando Verdasco. Nadal fell 6-3 3-6 7-5 to Verdasco in a match lasting three hours and 11 minutes in what was Verdasco\'s first win over the world number two at the 14th attempt, but Nadal was far from happy with the nature of the courts.
Nadal told reporters: \"Being able to move is very important for me and if I can\'t move well, I can\'t hit the ball well either. If things don\'t change, this will be one less tournament on the calendar for me. This surface destabilises the game. It is a completely different game and I don\'t want to take risks.\"
Verdasco\'s reward for his epic victory is a quarter-final clash with Czech sixth seed Tomas Berdych, who was a surprisingly comfortable 6-1 6-1 winner over Frenchman Gael Monfils.
Top seed Novak Djokovic found it far from straightforward to reach the last eight but he avoided the fate experienced by Nadal as he battled past Stanislas Wawrinka of Switzerland 7-6 (7/5) 6-4.
Seventh seed Janko Tipsarevic booked an all-Serbian quarter-final with Djokovic after coming through a three-set battle against Frenchman Gilles Simon 7-6 (7/3) 5-7 6-1.
Third seed Roger Federer shrugged off his close call in his second-round match with Milos Raonic as he swept aside French 14th seed Richard Gasquet 6-3 6-2 in just 58 minutes to reach the last eight.
Federer\'s next opponent is fifth seed David Ferrer, who edged his all-Spanish battle with Nicolas Almagro 7-6 (7/5) 3-6 7-6 (10/8).
Fourth seed Jo-Wilfried Tsonga went down 7-5 3-6 7-6 (7/2) to Alexandr Dolgopolov, and the Ukrainian will face Juan Martin Del Potro in the quarter-finals after he beat Marin Cilic 6-2 6-4.