<p>Rafael Nadal will return to the top of the world rankings after Tomas Berdych retired with a back injury during their China Open semifinal on Saturday.<br /><br /></p>.<p>Serb Novak Djokovic, who will lose top spot when the new rankings are announced on Monday, brushed aside Frenchman Richard Gasquet 6-4, 6-2 in the other semifinal to set up a mouth-watering final against arch-rival Nadal.<br /><br />Berdych, trailing 2-4 in the opening set, tweaked his back while running for a backhand slice and needed a medical time-out.<br /><br />He did return to court but after a few points decided he could no longer continue, handing the 27-year-old Spaniard an easy passage to Sunday's final.<br /><br />Serena motors on <br /><br />World number one Serena Williams and Serbian eighth seed Jelena Jankovic set up a final showdown in the women’s category after their contrasting victories in the semifinals on Saturday.<br /><br />The top-seeded American, who has now won 72 matches in 2013 and a prize purse of more than $9 million, hit 31 winners to thrash Poland's Agnieszka Radwanska 6-2, 6-2. <br /><br />But former world number one Jankovic had to rally from a set down to notch up her first career win against ninth seed Petra Kvitova 6-7 (7-9), 6-1, 6-1.<br />Paes-Nestor ousted<br /><br />Leander Paes and Daniel Nestor's bid to win their second title of the season together failed as they lost the semifinals of the China Open 6-3, 5-7, 8-10 to Italian pair of Fabio Fognini and Andreas Seppi.<br /><br />Meanwhile, Somdev Devvarman won his first round in the Shanghai Masters Qualifiers as he edged past local wild card Siyu Liu 6-1, 4-6 6-1.<br /><br />Sania triumphs<br /><br />Sania Mirza won her second title in a row as she lifted the China Open trophy with Cara Black, demolishing the challenge of Vera Dushevina and Arantxa Parra Santonja 6-2, 6-2.<br /><br />Del Potro, Raonic in final<br /><br />Top seed Juan Martin del Potro beat Nicolas Almagro of Spain 7-6 (9-7), 7-6 (7-1) in the semifinal of the Japan Open to set up a title clash with big-serving Milos Raonic of Canada.<br /><br />In-form Raonic, who lost to home favourite Kei Nishikori in last year’s final, defeated unseeded Ivan Dodig of Croatia 7-6 (7-4), 6-1.</p>
<p>Rafael Nadal will return to the top of the world rankings after Tomas Berdych retired with a back injury during their China Open semifinal on Saturday.<br /><br /></p>.<p>Serb Novak Djokovic, who will lose top spot when the new rankings are announced on Monday, brushed aside Frenchman Richard Gasquet 6-4, 6-2 in the other semifinal to set up a mouth-watering final against arch-rival Nadal.<br /><br />Berdych, trailing 2-4 in the opening set, tweaked his back while running for a backhand slice and needed a medical time-out.<br /><br />He did return to court but after a few points decided he could no longer continue, handing the 27-year-old Spaniard an easy passage to Sunday's final.<br /><br />Serena motors on <br /><br />World number one Serena Williams and Serbian eighth seed Jelena Jankovic set up a final showdown in the women’s category after their contrasting victories in the semifinals on Saturday.<br /><br />The top-seeded American, who has now won 72 matches in 2013 and a prize purse of more than $9 million, hit 31 winners to thrash Poland's Agnieszka Radwanska 6-2, 6-2. <br /><br />But former world number one Jankovic had to rally from a set down to notch up her first career win against ninth seed Petra Kvitova 6-7 (7-9), 6-1, 6-1.<br />Paes-Nestor ousted<br /><br />Leander Paes and Daniel Nestor's bid to win their second title of the season together failed as they lost the semifinals of the China Open 6-3, 5-7, 8-10 to Italian pair of Fabio Fognini and Andreas Seppi.<br /><br />Meanwhile, Somdev Devvarman won his first round in the Shanghai Masters Qualifiers as he edged past local wild card Siyu Liu 6-1, 4-6 6-1.<br /><br />Sania triumphs<br /><br />Sania Mirza won her second title in a row as she lifted the China Open trophy with Cara Black, demolishing the challenge of Vera Dushevina and Arantxa Parra Santonja 6-2, 6-2.<br /><br />Del Potro, Raonic in final<br /><br />Top seed Juan Martin del Potro beat Nicolas Almagro of Spain 7-6 (9-7), 7-6 (7-1) in the semifinal of the Japan Open to set up a title clash with big-serving Milos Raonic of Canada.<br /><br />In-form Raonic, who lost to home favourite Kei Nishikori in last year’s final, defeated unseeded Ivan Dodig of Croatia 7-6 (7-4), 6-1.</p>