Canada's Bianca Andreescu dropped a 7-6 (0), 7-5 decision to Marketa Vondrousova of the Czech Republic in first-round play at the Bett1Open on Wednesday.
Each player held serve through the opening set before the 53rd-ranked Czech took control in the tiebreaker by sweeping all seven points.
Andreescu, the world No. 35 from Mississauga, Ont., won only nine of 22 points on first serve in the second set.
Vondrousova will play Germany's Jule Niemeier in the second round of the WTA 500-level event.
The tournament is part of the grass-court swing ahead of Wimbledon. The Grand Slam tournament begins July 3.
Meanwhile, fellow Canadian Rebecca Marino outlasted China's Xiyu Wang 7-6 (5), 5-7, 6-3 in first-round play at the Rothesay Classic.
Marino, the world No. 90 from Vancouver, needed two hours 39 minutes to complete the victory.
She will face American Emina Bektas in the second round of the WTA 250-level tournament.
Bianca Andreescu