Australian No.1 Ashleigh Barty has continued her fine form on the North American hard courts as she reached the third round of the Cincinnati Open with a straight-sets victory over Kaia Kanepi.

Backing up her opening round win over Czech wildcard Marketa Vondrousova, 16th seeded Barty topped Estonian qualifier Kanepi 7-5 6-3 on Wednesday.

Defending US Open champion Sloane Stephens overcame a thumb injury to cruise into round three with a 6-3 6-2 win over qualifier Tatjana Maria.

The match was Stephens’ first since losing on Sunday to world No.1 Halep in the Canadian Open in Montreal.

Also advancing on Wednesday were 15th-seeded Belgian Elise Mertens, a 3-6 6-2 7-6 (7-1) winner over Swedish qualifier Rebecca Peterson; Russian Ekaterina Makarova, who routed French qualifier Alize Cornet 6-2 6-0; and Belarusian Aryna Sabalenka, who upset ninth-seeded Czech Karolina Pliskova 2-6, 6-3, 7-5.