"She was playing incredibly well and I was fully prepared not to be coming back. I just tried to mix things up and get her out of that zone because she was so in it. When she plays at her best she is incredibly tough to play against and I had to work incredibly hard to get my level up to her's.
"Every round is tricky. I am just really pleased to have come this far and with the tennis I am playing. I am looking forward to playing Petra, one of the best players in the world, and I am delighted to be in that position."