Defending champion Rafael Nadal slumped out of the Dubai tennis Open, losing 7-6 6-3 to unseeded Russian Mikhail Youzhny. Top seed and world number one Roger Federer also struggled but defeated seventh seeded Serb Novak Djokovic 6-3 6-7 6-3.

In the semi-finals, Federer will play fifth seeded German Tommy Haas, a 6-0 6-2 winner of Olivier Rochus of Belgium, while Youzhny will play unseeded Swede Robin Soderling, who beat Fabrice Santoro of France 6-1 6-7 6-0.

Youzhny's victory was not entirely unexpected, having won the Rotterdam title last Sunday, while Nadal has not reached a final since Wimbledon, and has not claimed a title since he won Roland Garros in June.