Roddick's next tournament was the 2009 China Open in Beijing, where he was the defending champion. In a shocking upset, he was defeated in the first round by Polish qualifier and No. 143 Łukasz Kubot. He also played doubles at the event with Mark Knowles. The pair reached the final, losing to Bob and Mike Bryan. Roddick was forced to retire from his first-round match at the 2009 Shanghai Masters against Stanislas Wawrinka while leading 4–3. It was later announced that Roddick would return to the United States to seek medical advice on a left-knee injury. Once again, he qualified for the Year-End Masters in London, securing the sixth spot. However, Roddick withdrew from the 2009 Valencia Open 500, the 2009 BNP Paribas Masters, and the 2009 Barclays ATP World Tour Finals due to the injury he suffered at the Shanghai Masters. He finished 2009 as the No. 7 in the world.