Kei Nishikori is a Japanese professional tennis player. He is the second male Japanese player to have been ranked in the top five in singles, and the only one to do so in the Open Era. Nishikori first reached his career-high singles ranking of world No. 4 in March 2015. He has won six ATP Tour 500 titles, six ATP Tour 250 titles and was runner-up at the 2014 US Open, making him the first man representing an Asian country to reach a major singles final. He also became the first man from Asia to qualify for the ATP Finals, and reached the semifinals in 2014 and 2016. In addition, Nishikori defeated Rafael Nadal to win the bronze medal at the 2016 Summer Olympics, bringing Japan its first Olympic tennis medal in 96 years. He holds one of the highest percentages of deciding-set wins in the Open Era and has the second-highest win percentage in matches extending to five sets, with a record of 28â8 and a win percentage of 77.78%.