|Top seed Sloane Stephens (photo by Daniel Ward)|
Here is the quarterfinal draw:
Sloane Stephens (1) vs. Madison Keys (8)
Stephens and Keys have played each other three times (once on clay, at the French Open), and Stephens has won all three matches in straight sets. Both players have excelled in Charleston: Stephens was the 2016 champion, and Keys was the runner-up in 2015.
Monica Puig vs. Danielle Collins (11)
Puig and Collins have played each other twice, both times on hard courts, and are tied 1-1. Puig reached the quarterfinals by upsetting 3rd seed Aryna Sabalenka in the third round.
Belinda Bencic (9) vs. Petra Martic (16)
Bencic and Martic have never played each other. Bencic's best showing at the Volvo Car Open occurred in 2014 (the tournament was the Family Circle Cup at that time), when she reached the semifinals.
Caroline Wozniacki (5) vs. Maria Sakkari (15)
Wozniacki and Sakkari have played each other only once, on a hard court in Wuhan, and Sakkari won that match. Wozniacki, the Charleston champion in 2011, was also the runner-up in 2009.