Mats Arne Olof Wilander is a Swedish former professional tennis player. He was ranked as the world No. 1 in men's singles by the Association of Tennis Professionals (ATP) for 20 weeks, including as the year-end No. 1 in 1988. Wilander won 33 career singles titles, including seven majors, and seven career doubles titles, including a major in men's doubles at Wimbledon. ATP world No. 1 from September 12, 1988 to January 29, 1989 — 20 weeks. Wiki link