Venus Williams came from a set down to defend her Mexican Open title, while David Ferrer defeated good friend and fellow Spaniard Juan Carlos Ferrero to end his 14-match winning streak on Saturday.

Top-seeded Fernando Verdasco was knocked out of the quarterfinals of the Mexican Open on Thursday by Juan Monaco, while women's No 1 seed Venus Williams fought back from 1-5 down in the final set to survive.

Venus and Serena Williams have won their fourth Australian Open women's doubles title, beating Cara Black and Liezel Huber 6-4, 6-3 at Rod Laver Arena.

Venus Williams advanced to the quarterfinals at Melbourne Park for the seventh time to set up a meeting with China's Li Na, who has never gone this far at the Australian Open.

The Williams sisters held court at the Australian Open on Thursday, a back-to-back Venus-Serena doubleheader that left the siblings still in the mix for yet another Grand Slam singles title.