Mats Wilander (born 22 August 1964, in Växjö, Sweden) is a former World No. 1 tennis player from Sweden. From 1982 through 1988, he won seven Grand Slam singles titles (three at the French Open, three at the Australian Open, and one at the US Open), and one Grand Slam men's doubles title (at Wimbledon). He won three of the four Grand Slam singles events in 1988 and finished that year ranked World No. 1. Although he never won the singles title at Wimbledon, Wilander twice won the Australian Open when that tournament was still played on grass courts. This makes Wilander one of only five men (along with Jimmy Connors, Andre Agassi, Rafael Nadal, and Roger Federer) to have won Grand Slam singles titles on grass courts, hardcourts, and clay courts. He and Rafael Nadal are the only men in tennis history to have won at least two Grand Slam singles titles on each of the three surfaces. Wilander won his fourth career Grand Slam singles title at the age of 20, the youngest man in history to have achieved that feat. In addition he also won eight Championship Series titles (1983–88) the precursors to the current Masters 1000.