No.2 seed Simona Halep brushed aside American qualifier Taylor Townsend 6-4 6-1 on Tuesday to take her place in the last 16 in Cincinnati.
Joining her in the third round was seventh seed Johanna Konta, a 6-3 6-3 winner over Dutchwoman Kiki Bertens.
Halep, a finalist in Ohio in 2015 and a semifinalist last year, could face 15th seed Anastasija in her next match after the Latvian beat in-form Chinese Peng Shuai in the first round.
Sevastova next faces Italy’s Roberta Vinci for a shot at Halep.
In a night match, Garbine Muguruza continued her impressive post-Wimbledon form with a 6-2 6-0 drubbing of Brazilian Beatriz Haddad Maia.
From 2-2 in the first set, the Spaniard rattled off 10 straight games to set up a third-round meeting with either Madison Keys or Daria Kasatkina.
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Earlier on Tuesday, Venus Williams cruised into the second round with a 6-2 6-0 win over fellow American Alison Riske.
She’ll next face in-form qualifier Ash Barty, who beat Varvara Lepchenko in straight sets for her seventh win in her past eight matches.
“I was hoping that maybe it was affecting her maybe more than me,” Williams said of the hot conditions.
“As professional athletes, if we decide to walk on the court, it doesn’t matter what you’re dealing with, you need to get out there and hold your head high and compete. And if you’re not prepared, do your best to prepare again.”
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Also advancing was wildcard Sloane Stephens, who beat Lucie Safarova for the second time in a week – after triumphing over the Czech in Toronto – to reach the second round.
Watch this.
Fantastic match point from @SloaneStephens to close out another hard-fought win over Lucie Safarova. #CincyTennis pic.twitter.com/pqtCTT6a8t
— WTA Insider (@WTA_insider) August 16, 2017
Another winner was No.11 seed Dominika Cibulkova; the Slovak ousted rising star Ana Konjuh in three sets and will next face Frenchwoman Alize Cornet, who scored an impressive win over the red-hot CiCi Bellis.
Yet 10th seed Agnieszka Radwanska and 12th seed Jelena Ostapenko were not so fortunate.
Radwanska fell 6-4 6-4 to Julia Goerges while Ostapenko managed just six games in a straight-sets loss to qualifier Aleksandra Krunic.
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