Muguruza breakspublished at 13:17 British Summer Time 13 July 2017
*Muguruza 2-0 Rybarikova
Rybarikova serves a 111mph serve - it's only her first service game.
30-15.
A poor attempted half-volley at the net results in punishment.
Muguruza adds to the pressure with a wrong-footed return from the back - break point.
And then... a double fault.
What a way to lose your service game - not good.