Agnieszka Radwanska continues her winning march
Poland's Radwanska is on an unmatched win run this year after claiming tournaments in Auckland and Sydney, and next faces one of two former world number ones, Ana Ivanovic or Jelana Jankovic.
In-form world number four Agnieszka Radwanska won her 12th match in a row Friday to power into the Australian Open fourth round at the expense of Heather Watson.
The fourth seed, who has never gone beyond the quarter-finals at Melbourne Park, was too strong for the Briton as she won 6-3, 6-1 in 84 minutes.
Poland's Radwanska is on an unmatched win run this year after claiming tournaments in Auckland and Sydney, and next faces one of two former world number ones, Ana Ivanovic or Jelana Jankovic.
She started steadily against Watson, who was looking to mirror fellow Brit Laura Robson's upset of eighth seed Petra Kvitova on Rod Laver Arena in the early hours of Friday.
They both held serve until Radwanska got the break in the fifth game with a powerful forehand down the line and Watson was unable to fight back, handing the world number four the set.
Radwanska needed treatment on the little finger of her right hand early in the second set but it didn't hinder her and she got the break she was after on Watson's opening service game.
After a day of searing heat on Thursday, the weather changed and the players were forced to endure a short stoppage at 3-0 while the mechanical roof was closed when it started raining.
But it was plain sailing afterwards for the Pole, whose best Grand Slam was Wimbledon last year when she made the final and was beaten by Serena Williams.