Little Sis and Big Sis are seeded number 12 in the doubles bracket and opened their title pursuit with a 6-3, 6-1 straight set win over Camila Giorgi of Italy and Stefanie Voegle of Switzerland that took only 70 minutes to complete..
They faced in the second round Vera Dushevina of Russia and Olga Gorvortsova of Bulgaria and they were dismissed in straight sets as well 6-1, 6-2 in 76 minutes.
In the doubles third round they faced fifth seeds Nadia Petrova of Russia and Katarina Srebotnik of Slovenia who took only 74 minutes to fall 6-2, 6-3.
The Williams sisters now face in the doubles quarterfinal round the Italian duo of Sara Errani and Roberta Vinci for a spot in the semis against the winner of the match between 4th seeded Russians Ekaterina Makarova and Elena Vesnina vs Spain's Silvia Soler-Espinosa and Carla Suarez Navarro.
The Spanish duo punched their quarterfinal ticket by upsetting the 5th seeded team Liezel Huber of the USA and Maria Jose Martinez Sanchez 7-6 (7-5), 2-6, 6-4.
The Williams sisters are in position to get their first Australian Open doubles title since 2010, but still have a lot of tennis left to play to get there.