The No.1-seeded Cibulkova was definitely tested in her match against Marina Erakovic, trailing a break early in the first set and facing a 3-1 deficit in the second set, but she overcame it all, 64 75.
Next up for Cibulkova is No.8 seed Zhang Shuai, who originally looked headed for a straight set victory up 61 31 but ended up having to grind past the always-dangerous Ajla Tomljanovic in three, 61 57 62.
Cibulkova has beaten Zhang in all three of their previous meetings, in straight sets too.
The big story of the day actually broke at night, as Caroline Garcia pulled off the upset of the week, rallying from a set and a break down to beat No.2 seed and fan favorite Eugenie Bouchard, 36 64 61.
"You have to give your opponent credit - she raised her level a lot and started serving much better in the second set," Bouchard said. "In the second set she was just going for it and really took it to another level. At the end of the day I need to be more aggressive than my opponent - I wasn't today."
Garcia's win over the World No.19 wasn't just her first Top 20 win, it was her first win over a Top 40 player - her best win before this week came against a No.47-ranked Zheng Jie at Wimbledon last year.
The Frenchwoman had never been to a WTA quarterfinal before this week - now, first WTA semifinal.
And to top it all off, she came into the tournament on a gloomy 10-match losing streak.
"The first set was close with a lot of breaks. I lost my serve so many times and knew I could do better," Garcia said. "So I tried to improve my serve after the first set and I started putting more pressure on her serve. I stayed focused and aggressive and I'm really happy I was able to keep winning today."
"The serve will be important for sure, and whoever will be more aggressive of the two of us will probably win the match," Garcia said. "I know her. I've played some doubles with her. It will be tough."