Vondrousova vanquished by Mertens
Second seed Elise Mertens advanced to the quarter-finals of the Ladies Open Lugano by edging defending champion Marketa Vondrousova over three sets on Friday.
Vondrousova was the champion at this event last year, when it was held on hard courts in Biel/Bienne, but there will be no repeat triumph on the clay of Lugano after Mertens' 6-2 5-7 7-5 victory.
The world number 20 dominated the first set, before a rollercoaster of a second saw six successive breaks of serve to leave it poised at 4-4.
Vondrousova snatched an all-important fourth break in game 12, however, and a similarly topsy-turvy decider saw Mertens ultimately prevail following over two and a half hours of action.
Mertens will face Mona Barthel, who came through 6-3 4-6 6-4 against Donna Vekic, while Kirsten Flipkens came from behind to defeat Aliaksandra Sasnovich 4-6 6-4 6-2 to set up a meeting with qualifier Vera Lapko, conqueror of Danka Kovinic.
Camila Giorgi had few problems in seeing off Alison Van Uytvanck 6-2 6-1, booking a clash with Aryna Sabalenka, and the last quarter-final sees Tamara Korpatsch take on Stefanie Voegele after their respective wins over Kathinka Von Deichmann and sixth seed Alize Cornet.