Garbine Muguruza made her debut at No. 1 on Monday, joining U.S. Open champion Rafael Nadal in making Spain the first country since the United States 14 years ago to top the WTA and ATP rankings.
Andre Agassi and Serena Williams were both No. 1 in 2003.
Muguruza, the Wimbledon champion in July, rose two spots from No. 3 on Monday after getting to the fourth round at Flushing Meadows for the first time. She is the 24th woman to lead the WTA since it introduced computer rankings in 1975 — and the second Spaniard, after Arantxa Sanchez Vicario.
Muguruza takes over at No. 1 from Karolina Pliskova, who fell to No. 4 with a quarterfinal defeat in New York one year after...