Flipkens, who is ranked 66th and had to qualify for the main draw, trailed 3-1 before winning 11 of the next 12 games.
''It's incredible that I've beaten her,'' Flipkens said. ''I tried to play my own game and switched a lot between attacking and defensive shots. Then Ana started to make more mistakes. I think that was because of the way I was playing.''
Ivanovic won the tournament in 2008 and 2010. Flipkens, who won her first title in Quebec City last month, will play Goerges for a place in Sunday's final.
''I feel like I adjusted really well,'' said Azarenka, who had never played Martic before.
Azarenka has not dropped a set in 11 consecutive matches. She won in Beijing last week and pulled out in the quarterfinals at Tokyo the week before.
''Every day I have to push myself,'' Azarenka said. ''It's not easy, even when it seems easy out there on court.''
- Victoria Azarenka
- Kirsten Flipkens
- Ana Ivanovic
- Petra Martic