most major men's singles titles in tennis history with Novak Djokovic, winning 22 titles. He stands alone in the Open Era as the player with the most clay court titles (63), consisting of an all-time record 14 French Open titles, 12 Barcelona Open titles, 11 Monte-Carlo Masters titles, and 10 Italian Open titles. His 14 French Open titles are a record at any single tournament, and he is the sole title leader in three key tiers of the ATP Tour; Grand Slam, ATP Masters 1000, and ATP 500. Nadal holds the record for the longest single-surface win streak in matches (81 on clay) and in sets (50 on clay) in the history of the Open Era. Nadal's dominance on clay is reflected by his honorific title as the "King of Clay", and he is widely regarded as the greatest clay-court player in history. Nadal's records and evolution into an all-court champion have established him as one of the greatest players in tennis history, with some former tennis players and analysts considering him to be the greatest tennis player of all time. Former tennis player and eight-time Grand Slam champion Andre Agassi picked Nadal as the greatest of all time because of the way the Spaniard "had to deal with Federer, Djokovic, and Murray in the golden age of tennis". Nadal leads the head-to-head record at majors against the other members of the Big Three and holds the record for the most majors won beating a Big Three member en-route (13). Nadal is one of two men, along with Agassi, to win the Olympic gold medal as well as the four majors in singles in his career, a feat known as a Career Golden Slam. He is the only male player in history to complete the Career Grand Slam and win an Olympic gold medal in both singles and doubles. He is one of four men in history, along with Roy Emerson, Rod Laver and Djokovic, to complete the double Career Grand Slam in singles. In 2010, Nadal became the first man to achieve the Surface Slam by winning majors on three different surfaces (clay, grass and hard courts) in the same calendar year. At the age of 24, he became the youngest player in the Open Era to complete the Career Grand Slam, and one of three men, along with Mats Wilander and Djokovic, to win at least two majors