MADRID - Novak Djokovic's frustration with the controversial blue clay at the Madrid Masters reached new heights after the world number one was beaten 7-6 6-3 by fellow Serb Janko Tipsarevic in the quarter-finals on Friday.

Djokovic and world number two Rafa Nadal, who was dumped out by Spanish compatriot Fernando Verdasco on Thursday, have complained bitterly all week about the slippery nature of the showcourt surface.

The top-ranked Serb again looked ill at ease as his bid to retain the title he beat Nadal to win in 2011 ended in a whimper while Tipsarevic secured a semi-final meeting with third seed Roger Federer.

Djokovic and Nadal have threatened not to return next year unless the traditional red courts are reinstated. Tournament organisers have blamed the slick surface on excessive pressing that prevents the clay from penetrating the hard base.

"I want to forget this week as soon as possible and move on to the real clay courts," said Djokovic who will chase a first French Open crown on the red dirt of Paris later this month.

"It took me at least a week to try to get used to this surface and somehow find a way to win matches and play a decent level of tennis," he told reporters.

"There is no discussion in my eyes, it's very simple. No blue clay for me."

Novak Djokovic of Serbia reacts after losing a point to Janko Tipsarevic of Serbia during their men's quarter-final match at the Madrid Open tennis tournament May 11, 2012.[Photo/Agencies]

Fluent Federer

Federer, the 2009 champion, has also expressed his opposition to the blue clay but the Swiss maestro has adapted to the conditions more effectively than the top two players and cruised to a 13th win against Spain's David Ferrer in 13 meetings.

Watched by Real Madrid soccer players including Cristiano Ronaldo and Xabi Alonso, the 16-times grand slam singles champion sealed a 6-4 6-4 victory with his seventh ace as he continued the pursuit of his fourth title this year.

Asked if he was the new title favourite following the exits of Djokovic and Nadal, Federer said: "Maybe. I have won it in the past so you figure as a player you can do it again.

"But all the other guys are highly ranked as well and can definitely run through the next couple of rounds so I am aware of that too," the 30-year-old added.

"I haven't played Janko that often so I don't quite know his game that well, like I know David's game for instance or Novak's or Rafa's.

"We'll see how that goes first and I hope I have a shot at the title on Sunday but obviously my focus is on Tipsarevic right now," said Federer.

Roger Federer of Switzerland returns the ball to David Ferrer of Spain during their men's quarter-final match at the Madrid Open tennis tournament May 11, 2012.[Photo/Agencies]

Seventh seed Tipsarevic, who beat Djokovic at the World Tour Finals in London last year, saved four break points in the first set before taking the tiebreak 7-2.

He squandered three match points on his rival's serve when leading 5-2 in the second set but made no mistake on his next service game to reach his first Masters Series semi-final on clay.

"I want to congratulate Janko for playing a great match today," Djokovic said. "I talked with him and he feels really good on the court.

"I am glad and I want to wish him to go all the way, I think he can. He's been playing great, no question about it."

Good sign

Tomas Berdych brought local favourite Verdasco, whose win against Nadal was his first in 14 attempts, crashing back to earth when he thrashed the 15th seed 6-1 6-2.

The sixth-seeded Czech, who also thumped 12th seed Gael Monfils 6-1 6-1 to reach the last eight, set up a semi-final against Juan Martin Del Potro.

The 2009 U.S. Open champion, undefeated in 10 clay matches this season and winner in Estoril last week, eased to a 6-3 6-4 victory over Ukrainian Alexandr Dolgopolov.

"I am really happy with my tennis, with my body and I am feeling really confident on clay," said Argentine Del Potro who had an eight-month layoff in 2010 due to a wrist injury.

"I don't feel any pain so it's a good sign for the next tournament and I think I'm getting better tournament by tournament," the 23-year-old added.