Dominika Cibulkova's poor North American swing continued on Monday, as she lost in the first round of the Western and Southern Open.
The Slovakian, ranked 13th, lost to Russia's Anastasia Pavlyuchenkova 6-3 6-3 at the WTA Premier event, making it three defeats in four matches for Cibulkova on the hard-court swing in the US and Canada.
Cibulkova, seeded 11th, was broken three times in each set, losing the final 10 points of the match as Pavlyuchenkova stormed into the second round in Cincinnati, Ohio.
Next up for Pavlyuchenkova is Italy's Karin Knapp, after the qualifier downed Swiss wildcard Belinda Bencic 6-2 7-6 (7-1).
Seeds to progress included Serbia's Ana Ivanovic (nine), Dane Caroline Wozniacki (12) and Italy's Flavia Pennetta (13).
Ivanovic arrested a break deficit in the second set against Romania's Sorana Cirstea before progressing 6-1 7-5.
Wozniacki had few qualms dismissing Slovakian Magdalena Rybarikova 6-2 6-3, while Pennetta battled past South African qualifier Chanelle Scheepers 6-3 6-7 (3-7) 6-2.
Qualifiers Pauline Parmentier and Taylor Townsend prolonged their weeks with first-round victories.
France's Parmentier was too good for Australian Casey Dellacqua 7-6 (7-4) 6-2, while American teenager Townsend edged Czech Klara Koukalova 6-3 4-6 7-5.
Locals Lauren Davis and Varvara Lepchenko were dealt early exits, the American pair bowing out in straight sets.
Wildcard Davis fell to Ukraine's Elina Svitolina 6-3 6-2, and Lepchenko was mastered by Australia's Sam Stosur 6-2 7-5.
There was better fortune for American Madison Keys, who eased past France's Alize Cornet 6-2 6-4.
China's Zhang Shuai got past British qualifier Heather Watson 6-3 2-6 7-5, and Belgium's Kirsten Flipkens outclassed Slovenian qualifier Polona Hercog 6-3 6-2.