Garbine Muguruza and Simona Halep led the way for seeds at the WTA Western and Southern Open, breezing through to the Round of 16.
Winners on Tuesday in Cincinnati included seeds Johanna Konta, Dominika Cibulkova and Venus Williams.
Elena Vesnina will face Caroline Wozniacki in the Round of 32, after she defeated Caroline Garcia in straight sets.
Sloane Stephens continued her solid run of form meanwhile, accounting for Lucie Safarova, as Anastasija Sevastova came from a set down to beat Shuai Peng.
GARBI CRUISES PAST QUALIFIER
Garbine Muguruza was in imposing form, taking just 65 minutes to defeat Beatriz Haddad Maia 6-2 6-0.
After trading breaks over the first four games, the 2017 Wimbledon champion continued to pounce on the Brazilian qualifier's second serve, winning 11 of 12 such points in the opening set.
Despite some trouble on her own serve, the Spanish fourth seed was able to deliver on the big points, holding in the last four games from 30-30.
Muguruza then claimed the bagel and the match, with a dominant 12 of 17 return points in the second set.
HALEP RECOVERS TO PROGRESS
Simona Halep also advanced to the Round of 16 in straight sets, with a 6-4 6-1 victory over American qualifier Taylor Townsend.
Similarly to Muguruza, Halep had early issues on serve, with four breaks in the opening six games.
From 2-4 down, however, the Romanian world number two reeled off four consecutive games including two love holds on serve.
Townsend's unforced error count proved the difference, ultimately. Both had 16 winners, but the American finished the match with 32 unforced errors compared to Halep's 22.
VENUS ACCOUNTS FOR COMPATRIOT
Venus Williams put in a commanding performance against Alison Riske, dropping just two two games to win 6-2 6-0.
The 2017 Australian Open and Wimbledon finalist needed just 66 minutes to go through, even after Riske broke back at 0-2 in the opening set.
After making the last 16 in Toronto last week, Williams was in good touch, finishing the match with a healthy differential of 27 winners to 16 unforced errors.
She will face Australian qualifier Ashleigh Barty, who defeated Varvara Lepchenko 6-4 6-4.