Maria Sakkari just can’t keep her foot out of trouble, which could be bad news for the rest of the WTA Finals field in Singapore.
The 21-year-old Greek, who has never played a WTA Tour final, advanced into the round of 16 with a 6-2, 7-5 win over 15th-seeded Madison Keys.
Kiki Bertens upset defending champion Simona Halep in the third round, and the tournament’s No. 2 seed Karolina Pliskova has won only two of her seven matches. Pliskova made 21 unforced errors, the most errors she has made in a WTA match this year. She has suffered through two knee injuries in 2018, including on-court left knee pain against Pliskova, and even had a calf injury during her match against Japan’s Naomi Osaka on Saturday.
Sakkari pulled off a huge upset over an injured Pliskova in the second round, and then beat 20th-seeded Petra Kvitova in the third.
Now Sakkari will face either No. 5-seeded Caroline Wozniacki or WTA Finals debutante Elina Svitolina in the round of 16. The winner will face either Kristina Mladenovic or Belinda Bencic in the semifinals.