Fernando Verdasco produced the shock of the tournament this Thursday as he produced a heroic fight-back to knock Rafael Nadal out of the Mutua Madrid Open.

Verdasco, who had lost his previous 13 meetings against the Spanish number one, came back form 4-1 down in the final set to win 6-3, 3-6, 7-5 in a marathon match lasting three hours and nine minutes.

Nadal looked as if he was going to complete his recovery after twice breaking Verdasco's serve in the final set, but his rival then broke him four times in succession to produce a stunning victory.

Speaking to the press afterwards, Nadal congratulated Verdasco and said he was a deserving winner, but again criticised the blue beaten clay court and said that if the same surface was used next year, he would not attend the tournament as he didn't want to risk injury.

"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 commented.

Veradsco will play sixth seed Tomas Berdych, who continued his progress into the last eight with a comfortable 6-1, 6-1 victory over Gael Monfils in a match that lasted just 50 minutes.

There was another shock in the men's singles as Alexandr Dolgopolov beat 4th seed, Jo-Wilfred Tsonga 7-5, 3-6, 7-6(2) in two hours and 18 minutes. He faces Juan Martin Del Potro, who trotted past Marin Cilic 6-2, 6-4.

Roger Federer, had few problems, progressing, however: the third seed was too good for Richard Gasquet and moved sedately into the last eight thanks to a 6-3, 6-2 win in slightly under an hour.

Federer faces a tough quarter final against Spain's David Ferrer who beat his fellow countryman Nicolas Almagro in a gruelling 7-6(5), 3-6, 7-6(8) match, which lasted seven minutes short of three hours in which the result was in doubt until the final ball.

With temperatures soaring in Madrid, it will be interesting to see whether or not Ferrer is able to recover for Friday's quarter-final.

Top seed and title holder Novak Djokovic is also into the quarter-final following a 7-6(5), 6-4 win against Stanislas Wawrinka.

In the women's competition, Serena Williams continued her progress into the last eight. Williams, who is seeded nine in Madrid, overcame the loss of the first set against number six seed, Caroline Wozniacki to win the last two set of her match 6-3, 6-2 to book a quarter-final meeting with Maria Sharapova, who had a walkover in her game after her rival Lucie Safarova was forced to pull out with a gastro-intestinal illness.

Speaking to the press after her win, Williams was relaxed and joked about the slippery conditions on the controversial blue clay court.

"I felt a bit like an ice-skater out there, but I can ice skate, so that's OK," she said, before admitted she would be the underdog against Sharapova.

Qualifier, Lucie Hradecka continued her progress thanks to a 6-2, 7-5(5) victory over Ekaterina Makarova, while Varvara Lepchenko, another qualifier, is also through after beating Anabel Medina Garrigues 6-1, 6-7, 6-3.

Finally number four seed Agnieszka Radwanska is also into the last eight after a narrow, 7-6(1), 6-4 triumph against Italian, Roberta Vinci.