Britain's Harriet Dart lost 7-6 (7-3) 6-4 to Anna Bondar in the last 16 of the Transylvania Open.
Dart, the 26-year-old ranked 90th in the world, had seven break points against the Hungarian, 25, but could only take one.
That came in the first set when both players broke each other once before Bondar, ranked 62nd in the world, took it on a tie-break.
One break of serve was enough for Bondar to take the second set.