US Open 2018: Angelique Kerber and Petra Kvitova through
Fourth seed and former champion Angelique Kerber overcame a second-set wobble against Sweden's Johanna Larsson to make the US Open last 32.
The German, who had never lost a set in three previous matches with Larsson, eventually prevailed 6-2 5-7 6-4 over two hours and 24 minutes.
Kerber will play Slovakia's world number 35 Dominika Cibulkova next.
Czech fifth seed Petra Kvitova got past a stubborn display from China's world number 90 Wang Yafan to win 7-5 6-3.
Kvitova, 28, broke late to seal the opener after initially letting a 4-1 lead slip and Wang's consistent groundstrokes and a solid serve kept the world number 90 in touch in the second set.
American Madison Keys, who lost last year's final to Sloane Stephens, beat compatriot Bernarda Pera 6-4 6-1.
Kvitova next plays 20-year-old Belarusian Aryna Sabalenka, who won the New Haven title earlier in August.
Sabalenka beat 2010 runner-up Vera Zvonareva 6-3 7-6 (9-7) to make the last 32.
She is joined by her compatriot Aliaksandra Sasnovich who upset Russia's in-form 11th-seed Daria Kasatkina 6-2 7-6 (7-3)
Sasnovich will face Naomi Osaka - who clinched her biggest career title at Indian Wells in March - after the Japanese beat Julia Glushko 6-2 6-0.