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Japan's Kei Nishikori reached a career-high ATP ranking of No. 56 in 2009, but then a right elbow injury and surgery ended his season and forced him off the tour for six months. The 20-year-old righthander battled his way back to the top 100 in the rankings in 2010 by winning more singles titles than any other man on the USTA Pro Circuit with four, including back-to-back titles in Savannah, Ga., and Sarasota, Fla. He finished the year ranked 98th in the world.