Djokovic beats Federer to earn Nadal clash; Serena injury blow May 19, 2012 -- Updated 2016 GMT (0416 HKT) Novak Djokovic celebrates his semifinal win over Roger Federer in the Rome Masters. Novak Djokovic to play Rafael Nadal in Rome final Djokovic sees off Roger Federer in 6-2 7-6 in their semifnal Serena Williams pulls out before women's semifinal against Li Na Li Na to face Maria Sharapova in women's title match (CNN) -- World number one and defending champion Novak Djokovic cruised past Roger Federer in straight sets 6-2 7-6 to reach the final of the Masters 1000 event in Rome Saturday. The Serbian will face Rafael Nadal in a repeat of last year's final. Nadal dominated David Ferrer 7-6 6-0 in the earlier semifinal to go into his seventh final at the clay court tournament in the Italian capital. Most of the attention was on the clash between Djokovic and Federer under the Foro Italico lights, but it took until the second set for the match to warm up. Djokovic took the opener in fine style with two breaks of service and moved ahead in the second with a further break. Serving for the match at 5-4, he forced a match point, saved by Federer, who proceeded to break back to level at 5-5. Roared on by the crowd, Federer took the match into tiebreaker, but after a grueling 25 stroke rally the top seed gained the mini-break. It proved crucial and at 5-4 Djokovic won his next two service points to close out the match. It's just life. I've been playing a lot, and my body is just getting used to playing a lot of matches again, that's all Serena Williams Earlier, five-time Rome winner Nadal fought off compatriot Ferrer, the nub of the encounter a first set tiebreak which he took 8-6. Ferrer's challenge subsided and he did not win a further game. In the WTA tournament in Rome, Serena Williams, who won last week in Madrid, pulled out before the start of her semifinal with Li Na of China with a back injury. The ninth seed did not want to risk the niggle ahead of the French Open as she explained to gathered reporters. I've been playing a lot, and my body is just getting used to playing a lot of matches again, that's all. Reigning French Open champion Li will now face reigning Italian Open champion Maria Sharapova in the final. Sharapova continued her superb year with a 6-3 6-4 win over 12th seed seed Angelique Kerber. Germany's Kerber, who put out Petra Kvitova in a late night match Friday, was always second best against the Russian second seed.