Monica Seles is a former professional tennis player who represented Yugoslavia and the United States. She was ranked as the world No. 1 in women's singles by the WTA for 178 weeks, and finished as the year-end No. 1 three times. Seles won 53 career singles titles, including nine majors: eight as a teenager while representing Yugoslavia and the final one while representing the United States. WTA world No. 1 from March 11, 1991 to August 4, 1991 — 21 weeks. Wiki link