BIEL, Switzerland (AP) -- Former U.S. Open runner-up Roberta Vinci lost on the opening day of the first Biel Ladies Open on Monday.
The fourth-seeded Italian, now ranked No. 35, lost to 58th-ranked Kristyna Pliskova of the Czech Republic 6-4, 6-4.
Their first-round match opened the main draw on the 2,500-capacity show court at Swiss Arena as the indoor hard-court event debuted on the WTA Tour.
The other seeded player in action quickly followed Vinci on her way out. Eighth-seeded Monica Niculescu of Romania lost to Elise Mertens of Belgium 6-2, 6-2.
Also Monday, Mona Barthel of Germany beat Jana Cepelova of Slovakia 6-3, 6-4.