Serena Williams knocked out by German teenager Nick Krygios . `` I think I was in a bit of a zone out there , '' he told reporters after setting up a last-eight clash with Canadian eighth seed Milos Raonic , who beat Japan 's Kei Nishikori 4-6 6-1 7-6 6-3 . ` Nick Krygios beaten in half sets by Angelique Kerber . Roger Federer to face compatriot Stanislas Wawrinka . Nick Krygios retires from doubles with viral illness .
Serena Williams knocked out by German teenager Nick Krygios . Nick Krygios beaten in half sets by Angelique Kerber . Roger Federer to face compatriot Stanislas Wawrinka . Nick Krygios retires from doubles with viral illness .