Former Wimbledon champion Petra Kvitova defeated world No.27 Lucie Safarova 7-6 (4), 6-2 to snatch her 300th career victory, reaching the last four of the Sydney International Wednesday.
The second seed will face Bulgarian Tsvetana Pironkova, who is a 2010 Wimbledon semi-finalist, upsetting third seed Sara Errani of Italy 7-6 (2), 6-3, reports Xinhua.
American Bethanie Mattek-Sands, who upset top seed Agnieszka Radwanska, retired with a back injury while trailing fellow American Madison Keys 2-3 in their quarter-final match.
Keys will face German fifth seed Angelique Kerber, who ousted Spaniard Carla Suarez Navarro 6-2, 6-4.
Mattek-Sands said she withdrew to nurse her body through to next week's Australian Open and beyond.
