Elina Svitolina suffered an error-strewn loss in the first round of the Birmingham Classic, while Karolina Pliskova was among the seeds to advance.
World number seven Svitolina was beaten 6-3 3-6 6-4 by Margarita Gasparyan, the Ukrainian's cause not helped by five double faults and 15 unforced errors in the opening set in her first match since losing in the last 32 at the French Open.
Third seed Pliskova experienced no such problems as the wildcard did not face a break point in seeing off Mihaela Buzarnescu 6-3 6-4, the Czech recording her 30th victory of 2019, the third-most among those on the WTA Tour.
Johanna Konta, a semi-finalist at Roland Garros, also advanced courtesy of a 6-4 6-2 success over Anett Kontaveit.
Yet fifth seed Aryna Sabalenka was ousted as Hsieh Su-wei beat a top-10 player for the fourth time this season.
Hsieh, who was a break down in the decider, won 6-3 2-6 7-6 (7-1) to set up a second-round clash with her doubles partner Barbora Strycova.