Anna Karolina Schmiedlova survived a first-set scare to defeat Kristyna Pliskova and reach round two of the Korea Open on Monday.
Schmiedlova, seeded second in Seoul, is ranked some 89 places above her Czech opponent, but a disjointed performance on serve saw her broken twice during a poor first set.
However, the Slovak regained her composure in the second and, after saving three break points in game three, made the crucial break for a 4-2 lead.
With the momentum in her favour, Schmiedlova broke in game three of the decider and fended off three break points when serving at 4-3 before going on to see out the match.
Mona Barthel and Julia Gorges – seeded fifth and seventh – had little trouble in reaching round two, the former beat Jang Su-jeong 6-0 7-6 (7-2), while the latter was a 6-1 6-4 victor over Lara Arruabarrena.
Eighth seed Alison Van Uytvanck did not have it all her own way against Andreea Mitu, the Belgian came from behind to win 3-6 6-1 7-6 (7-2).
In other matches, Polona Hercog beat Lauren Davis 6-1 6-3, Mariana Duque-Marino was a 3-6 7-6 (7-5) 6-2 victor against Kiki Bertens, and Klara Koukalova retired hurt when trailing Magdalena Rybarikova 6-1 2-1.