Mats said there was nothing Errani could do against the superior serve and power of Williams - who is "on a mission" as she prepares to face Maria Sharapova in the final.
Our expert says Sharapova has some cause for hope despite the incredible form of Williams, as the clay suits the world number two and defending champion.
Mats also turned his expert eye to Sharapova's semi-final win over Victoria Azarenka, which was an altogether closer affair.
Finally, Mats previewed Friday's huge semi-final between Rafael Nadal and Novak Djokovic, which pits two of the world's best against each other.
- Sports & Recreation
- Serena Williams
- Mats Wilander
- Maria Sharapova
- Sara Errani