SHANGHAI - David Rudisha set his sights on breaking the Shanghai Diamond League record on Thursday as he steps up his campaign for the first back-to-back Olympic 800 metres titles in 52 years. The Kenyan said he was hoping for improvement in his second outing of the season, after clocking one minute 44.78 seconds in Melbourne in March. "I want to keep on improving every time. Of course, my ultimate aim is to be at the top form in August for Rio Olympics," he told a news conference in Shanghai. "I'm also looking forward to improve from my last time in Australia," he said. "I'm looking forward for something like 1:43-and-a-half." The Shanghai meet record is 1:44.63, set by now-retired Kenyan Wilfred Bungei in 2008. Rudisha set an amazing world record of 1:40.91 to win gold in the London Games in 2012.