Top-seeded Mona Barthel of Germany pulled out with a shoulder injury while trailing 6-2, 4-3 to the 725th-ranked Lisa-Maria Moser in the second round of the Gastein Ladies on Wednesday.
Playing in her first WTA event, Moser broke twice to take the opening set and the Austrian wildcard was a break up in the second when the 31st-ranked Barthel withdrew.
Barthel, who was looking to reach her fourth quarterfinal of the season and first since winning in Paris in February, took over the top seeding after defending champion Alize Cornet of France pulled out with a shoulder injury.
In the quarterfinals, Moser will play Andrea Hlavackova of Czech Republic, who rallied to beat Viktorija Golubic of Switzerland 5-7, 6-1, 6-0.
Also, No. 8 Karin Knapp of Italy advanced to the last eight after beating Alexandra Cadantu of Romania 7-6 (5), 4-6, 6-1. Knapp will face second-seeded Annika Beck of Germany or Mandy Minella of Luxembourg.
In first-round play, 2007 finalist Yvonne Meusburger routed Jasmina Tinjic of Bosnia 6-0, 6-0. Coming off her second career final in Budapest three days ago, the Austrian conceded only three points on serve, including a double-fault.