Sydney - Tsvetana Pironkova on Wednesday stretched her Sydney International winning streak to 14 matches with a straight sets victory over Barbora Zahlavova Strycova to reach the semi-finals.
The Bulgarian, who again had to fight her way through qualifying to reach the main draw, ousted the world No 25 Czech 6-4, 6-1.
It continued an amazing run at the tournament by the Bulgarian world No 67, who was a shock winner in 2014 after battling through the three rounds of qualifying to beat Germany's Angelique Kerber in her eighth match at Sydney Olympic Park.
Pironkova, 27, has once again had to do things the hard way to reach the last four after coming through qualifying to reach the main draw.
"I'm super excited. To be honest, I didn't really believe that I could go this far again because I had to start from quallies again," Pironkova said.
"It's obviously a very hard thing to do considering the quallies nowadays is not like it was 20 years ago.
"It's also a very strong tournament. So I'm incredibly happy that I'm winning again, so I will just try to do it again," she said.
Pironkova said as the defending champion she was annoyed not to receive a wildcard into the main draw of the tournament.
"I was hoping that I would get. I applied but obviously didn't get it," she said.
Last year's win in Sydney is the only WTA success of Pironkova's career.
Early morning finish
Pironkova now faces two-time Wimbledon champion and second seed Petra Kvitova in a repeat of their semi-final match-up last year which the Bulgarian won.
Kvitova fought back to oust Australia's Jarmila Gajdosova 4-6, 6-3, 6-4 in a night match.
World No 22 Karolina Pliskova also won through to the semi-finals after seeing off Spain's Carla Suarez Navarro, 4-6, 6-4, 6-0.
The 22-year-old from the Czech Republic now faces Angelique Kerber for a place in Saturday's final.
Kerber, who had an early morning finish in the previous second round, recovered to overcome Spaniard Garbine Muguruza 0-6, 6-1, 6-4.