Nikolay Vladimirovich Davydenko (Russian: Никола́й Влади́мирович Давыде́нко, ; Ukrainian: Микола Володимирович Давиденко, Mykola Volodymyrovych Davydenko) is a Russian 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 has been reaching the semi-finals, which he has done 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 to date was winning the 2009 ATP World Tour Finals, and he has also won three ATP Masters Series.