BEIJING (AFP) - Ukraine's heptathlon silver medallist Liudmyla Blonska has failed a drugs test, the IOC confirmed Wednesday as the first high-profile doping failure hit the Beijing Olympics on the 13th day. The 30-year-old had failed her A sample and the result of the B sample would be known Thursday. Blonska faced a lifetime ban if both samples prove positive after serving a previous suspension for taking stanozolol, the anabolic steriod used by disgraced sprinter Ben Johnson. "There has been an adverse finding in her A sample against her (Blonska)," and IOC source told AFP. International Athletics Federation president Lamine Diack confirmed an investigation was underway. "The procedure is running. The B-sample will no doubt be opened today and a decision taken tomorrow." If confirmed, Blonska would be the fifth athlete to test positive, although the previous four only involved one podium finisher - North Korean shooter Kim Jong-Su, a minor medallist. Meanwhile Jamaican sprinter was Usain Bolt, fuelled by chicken nuggets and yam in his bid to be the first man in 24 years to win the Olympic sprint double on Wednesday. It's Bolt's favoured event, and he predicted when he smashed his world record in winning the 100m that he would repeat the double last achieved by Carl Lewis in 1984. The 21-year-old Bolt owns the three fastest 200m times this season, ran an effortless semi-final on Tuesday and joked afterwards he was only jogging. "I was just trying to make sure I was in a good position, keeping an eye on the board and seeing where everyone else was," he said, but indicating Michael Johnson's world record of 19.32 seconds may be out of reach. "I'm not really worried about the world record," Bolt said. "I'm just coming here to win. That's the aim for me." Defending champion Shawn Crawford and 100m bronze medallist Walter Dix, both members of a US track team that has failed to excel in Beijing, figure as Bolt's main rivals. China continues to hold a commanding lead on the medal's table with 44 compared to 26 for the the United States and 16 for Great Britain with 93 finals remaining before the Games close on Sunday. Yin Jian lifted China further ahead winning the women's windsurfing, but the Games hosts had no luck in a preliminary round baseball match when crushed 17-1 by Cuba with the match called off in the seventh inning under the sport's mercy rule. Lithuania ended China's hopes of an Olympic basketball medal when they despatched Yao Ming's side 94-68 in the quarter-finals. Russian open water superstar Larisa Ilchenko entered the record books as the first women's 10km swimming marathon champion when the sport made its debut on Wednesday. Ilchenko, unrivalled in open water swimming for the past four years, overtook Great Britain's Keri-Anne Payne in a sprint finish to win the gruelling event in just under two hours in the water. It was the first of three golds for Russia with Buvaysa Saytiev winning his third Olympic crown in the 74kg wrestling final and Anastasia Davydova teamed with Anastasia Ermakova to win the synchronised swimming. South Africa's Natalie du Toit, created a record as the first amputee to qualify for the Olympic Games, finished 16th in the 25-strong field women's swimming marathon field and pledged to be back in 2012 to do better. "I don't even think about not having a leg and if I want to keep competing I will have to continue to qualify with the able-bodied. For me it's not about the disability at all," said du Toit who lost her left leg in a motorcycle accident seven years ago. Another sport making its Olympic debut, BMX racing, saw American professional Mike Day coming out tops from the men's qualifying rounds.