Federer goes to 12-0 versus Youzhny Roger Federer, shown in a November 2011 tournament, on Thursday advanced to the semifinals of the Dubai Duty Free Tennis Championship by improving to 12-0 lifetime against Mikhail Youzhny. DUBAI, United Arab Emirates, March 1 (UPI) -- Roger Federer kept his record perfect versus Mikhail Youzhny and advanced Thursday to the semifinals of the Dubai Duty Free Tennis Championships. Federer, the No. 2 seed, stopped Youzhny 6-3, 6-4. He is 12-0 lifetime against the Russian, including 4-0 in Dubai. Youzhny has won a total of three sets in the 12 matches. Federer lost 13 points on serve and didn't face a break point Thursday. He had one break in each set as Youzhny fought off nine of the 11 break points he saw. World No. 1 Novak Djokovic, who beat Federer in the 2011 finals in Dubai, is headed to the semifinals after a 6-1, 7-6 (8-6) win over seventh-seeded Janko Tipsarevic. Djokovic also didn't allow Tipsarevic a break-point chance. He'll go against third-seeded Andy Murray on Saturday. Murray defeated No. 5-seeded Thomas Berdych 6-3, 7-5 behind four service breaks. Juan Martin del Potro broke open a tight match and beat fourth-seeded Jo-Wilfried Tsonga 7-6 (7-1), 6-2. Del Potro, seeded eighth, took control in the tiebreak and won the first four games of the second set. Djokovic owns a 7-4 record versus Murray. That includes a thrilling five-set, 5-hour battle in the semifinals at the Australian Open this year. Federer is 9-2 against del Potro. Their signature match is a five-setter won by del Potro in the finals of the 2009 U.S. Open.