Elise Mertens beat the rain and Czech teenager Marketa Vondrousova to reach the quarter-finals of the WTA event in Switzerland
The pair toiled for more than two-and-a-half hours through rain drops before the second-seeded Belgian won 6-2 5-7 7-5.
With play affected by the weather for a fifth-straight day, plans to complete both the second round and quarter-finals on Friday were put on hold.
But Kirsten Flipkens and Camila Giorgi did manage to complete respective upset second-round victories over Aliaksandra Sasnovich and Alison van Uytvanck.
Belarusian eighth seed Sasnovich led Flipkens by a set prior to Friday's first rain delay, and built a double-break advantage upon resumption in the second set.
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But Flipkens won six of the next seven games to tie the match before advancing 4-6 6-4 6-2 into her first quarter-final of the season.
Giorgi and Van Uytvanck played five games in the first set on Thursday before play was suspended, and it was the Italian who eased through 6-2 6-1.
Vera Lapko eased into the final eight with a 6-2 6-3 win over fellow qualifier Danka Kovinic.
Germany's Mona Barthel followed up the shock scalp of Svetlana Kuznetsova on Thursday with a 6-3 4-6 6-4 victory over Donna Vekic.
