COPENHAGEN, Denmark (AP) -- German qualifier Mona Barthel knocked out fifth-seeded Barbora Zahlavova Strycova 7-6 (2), 6-4 in the second round of the Sony Ericsson Open on Wednesday.
The 20-year-old Barthel, playing in only her third WTA main draw, won her first tour-level match only this week.
Eighth-seeded Italian Alberta Brianti also advanced to the quarterfinals after a hard-fought 3-6, 6-4, 6-1 win over Zuzana Kucova of Slovakia.
Also, Alona Bondarenko of Ukraine beat Kathrin Woerle of Germany 6-0, 1-6, 6-2, while 112th-ranked Petra Martic of Croatia hit a dozen aces in defeating Simona Halep of Romania 6-3, 5-7, 7-5 in 2 hours, 50 minutes.
Top-ranked Caroline Wozniacki faces Angelique Kerber of Germany in the second round on Thursday.