Eighth seed Eugenie Bouchard suffered a shock first-round defeat of the Ladies Open Lausanne, letting a match point slip in a three-set defeat to Tamara Korpatsch.
Former Wimbledon finalist Bouchard appeared poised to claim a hard-fought win at 5-4 in the decider but was unable to convert her opportunity to wrap up the match, allowing Korpatsch to complete an unlikely comeback.
The world number 145 broke to level at 5-5 and, after a love hold, pounced on another poor Bouchard service game to complete a 2-6 6-4 7-5 win in two hours and 36 minutes.
Bouchard has now lost her last seven matches, her last win coming in a run to the quarter-finals at Dubai in February.
Seventh seed Daria Gavrilova avoided a surprise exit as she saw off wild card Ylena In-Albon 7-5 4-6 6-3, with second seed Caroline Garcia enjoying much more serene progress in a 6-2 6-3 defeat of Antonia Lottner.
Qualifiers Anastasia Potapova and Jasmine Paolini also prevailed, along with Fiona Ferro, Han Xinyun and Bernarda Pera.
Meanwhile, at the Bucharest Open, seeds Viktoria Kuzmova, Laura Siegemund and Aliona Bolsova beat Dalila Jakupovic, Anhelina Kalinina and Varvara Flink respectively.
Ysaline Bonaventure and Elena Rybakina also enjoyed victories.