Japan\'s Kei Nishikori continued his strong season by upsetting number one seed Nicolas Almagro from Spain 6-7 (5/7), 6-4, 6-4 at the Malaysian Open Friday to reach his third semi-final of 2011. The 54th-ranked Japanese eighth seed set up a last four meeting against Serb third seed Janko Tipsarevic, who was 3-1 up in his first set when 2009 champion Nikolay Davydenko retired with a left hip injury. \"I don\'t know what the injury is exactly yet,\" said 30-year-old Davydenko. \"I\'m a bit scared as I\'ve never had anything like it before. \"I\'ll still go to Beijing, maybe wait a few days and see what the pain is like. It\'s a shame. I always enjoy this tournament and I hope to come back again in the future.\" In the other semi-final, unseeded Marcos Baghdatis from Cyprus will face second seed Viktor Troicki after both enjoyed straight sets wins. Troicki, who helped Serbia to the Davis Cup title last year, booked his place in the last four with a 6-4, 6-4 win over Russian Dmitry Tursunov. It was tougher for former Australian Open finalist Baghdatis, who had to work for just under 90 minutes to upset Austrian fourth seed Jurgen Melzer 6-3, 7-6 (7/3). Neither man had lost a set this week entering their match at the Putra stadium. Baghdatis, ranked 60th, struck 13 aces to set up the match against Troicki. The pair met twice last season, winning one match apiece. Troicki was largely untroubled by Tursunov. \"It\'s helping my confidence to get some wins here,\" said the Serb. \"I lost early in Cincinnati (August) and at the US Open so my confidence wasn\'t great coming in. \"Getting to another ATP semi-final helps a lot.\" Troicki said that solid returns from both men led to the ten break point chances in the match. \"I controlled the second set at 4-0 and 5-1, but then I lost one serve and he\'s back to 5-4. \"My focus went down a bit maybe, but it was good to close it out in two sets,\" he said.