Nikolay Vladimirovich Davydenko ( ; born 2 June 1981) is a Ukrainian-born Russian former professional tennis player. He achieved a career-high singles ranking of World No. 3 in November 2006. Davydenko's best result in a Grand Slam tournament was reaching the semi-finals, which he accomplished on four occasions: twice each at the French Open and the U.S. Open, losing to Roger Federer in all but one of them. His biggest achievement was winning the 2009 ATP World Tour Finals, and he also won three ATP Masters Series. In mid-October 2014 Davydenko retired from playing professionally . Personal life Nikolay was born on June 2, 1981, in Sievierodonetsk, at that time Severodonetsk, Ukrainian SSR, Soviet Union, in the family of Vladimir and Tatiana Davydenko. He started playing tennis at the age of 7 with his brother Eduard, nine years his senior. At the age of 11, he left his hometown for the Russian city of Volgograd. The initiator of the departure was his brother Eduard who worked as a children's tennis coach in Volgograd at that time. He motivated his brother's move by the fact Nikolay's professional growth at home was impossible. Four years later, in 1996, the brothers decided to move to Salmtal, Rhineland-Palatinate, Germany for the same reasons. The brothers had lived in Germany for three years and then applied for German citizenship but the German Tennis Federation did not support the application, and as a result, they returned to Russia. In 1999, at the age of 18, Nikolay changed his Ukrainian citizenship (granted at 14 by default) to the Russian one. In 2007, he applied for Austrian citizenship (so as to obtain dual citizenship), unsuccessfully. He was motivated by the difficulties obtaining travel visa with the Russian passport. And he wasn't given one because a sports minister in Austria was against while the other local authorities seemed to approve it. According to Davydenko, the Austrian minister said: "It's too soon". He and his wife Irina, a former model (m. 2006), have three children, an older daughter named Ekaterina (born 2012) and two sons — Konstantin (b. 2015) and Dmitry (b. 2017). His nephew Philipp is a former professional tennis player and ATP/WTA coach. Davydenko speaks Russian as a native language, German as his second one, and English. Tennis career Early career Davydenko started playing at the age of seven with his brother, Eduard. During his junior tennis years,