The American teenager Madison Keys has shocked the fourth seeded Czech Petra Kvitova at the Australian tennis Open.
Petra Kvitova Photo: PHOTOSPORT
The 19-year-old beat the two-time Wimbledon champion 6-4 7-5 to reach the fourth round.
New Zealander Michael Venus is through to the third round of the doubles with Austrian partner Oliver Marach.
The unseeded pair stunned the fifth seeds Alexander Peya of Austria and the Brazilian Bruno Soares 6-4 7-6.
Michael Venus (left) celebrates a point with Oliver Marach Photo: Photosport
Ninth seed David Ferrer was pushed to four sets by the equally industrious Frenchman Gilles Simon, the Spaniard beating the 18th seed 6-2 7-5 5-7 7-6 in more than three and a half hours.
Ferrer's reward is a clash with Japanese fifth seed Kei Nishikori, who beat American Steve Johnson 6-7 6-1 6-2 6-3.
Also through to the last 16 are the top seeds Novak Djokovic and Serena Williams, her sister Venus Williams, defending champion Stanislas Wawrinka, eighth seed Milos Raonic, former champion Victoria Azarenka and Polish sixth seed Agnieszka Radwanska.
Spain's Fernando Verdasco made Djokovic work hard before the Serb won it 7-6 6-3 6-4, while Serena Williams needed three sets to beat Ukrainian Elina Svitolina 4-6 6-2 6-0.
Venus Williams also struggled before putting away rising Italian Camila Giorgi 4-6 7-6 6-1.
Venus Williams in action in Melbourne Photo: Photosport
Belarussian Azarenka beat Auckland semi-finalist Barbora Zahlavova Strycova of the Czech Republic 6-4 6-4, while fourth seed Wawrinka had few problems with Jarkko Nieminen, the Swiss putting away the Finn 6-4 6-2 6-4.
Canada's Raonic knocked out Benjamin Becker, the German who eliminated Australian veteran Lleyton Hewitt, 6-4 6-3 6-3.
The Pole Radwanska beat Varvara Lepchenko of the USA 6-0 7-5.
