KEY BISCAYNE, Fla. (AP) Sloane Stephens advanced Monday to the Miami Open quarterfinals by beating No. 3-ranked Garbine Muguruza in a matchup of 2017 Grand Slam champions, 6-3, 6-4.
Stephens, a South Florida native and the No. 12 seed, earned her fifth career victory over a top-five player. Stephens won her first major title at the U.S. Open in September, but arrived at Key Biscayne with a record of only 3-4 this year.
Muguruza, who won Wimbledon last summer, has also struggled in 2018 and fell to 8-6.
Qualifier Thanasi Kokkinakis, who upset Roger Federer in the second round, was unable to build on the biggest win of his career. Fernando Verdasco rallied from two mini-breaks down in the decisive tiebreaker and beat Kokkinakis 3-6, 6-4, 7-6 (4).
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