It started badly for the former world set who lost the first set by a whole 1-6 against 91-ranked Bouzkova from the Czech Republic.

- She did everything right, had a really good match plan and moved fantastic. I had to make some adjustments, Williams says.

The 21-year-old Bouzkova showed no nerves even though it was her first WTA semifinal, but when her youth idol Williams showed the class she took over the match.

Now home bianca Andreescu, 19, is waiting for the final. The American, who is currently ranked 10th in the world, is hoping for a nice shape message ahead of the US Open, which begins August 26. There, she is chasing her 24th grand slam title, which would then hit legendary Margaret Courts record.