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," said Djokovic. (Reuters)