Novak Djokovic and Rafa Nadal moved a step closer to another possible final showdown after recording straight-set wins in the quarter-finals of the Rome Masters today. Holder and top seed Djokovic survived a tight first set to beat Frenchman Jo-Wilfried Tsonga 7-5, 6-1 while Nadal recorded an impressive 6-4, 7-5 victory over in-form Czech Tomas Berdych.Djokovic and Tsonga exchanged two service breaks apiece but the Serb clinched the opening set. The Serb then ran away with the second set to set up a clash with either world number two Roger Federer or Andreas Seppi of Italy. Nadal, who slipped behind Federer in the rankings after the Swiss won the Madrid title last weekend, produced an outstanding performance to beat seventh seed Berdych. In the semi-finals, Nadal will meet fellow Spaniard David Ferrer, who edged out Richard Gasquet of France 7-6 6-3.