Williams advances to 4th round at Australian Open

Serena Williams advanced to the fourth round of the Australian Open, easily beating Greta Arn of Hungary 6-1, 6-1 in the opening night match Saturday at Rod Laver Arena.

Five-time Australian champion Williams, who came into the tournament with a left ankle injury, seems to be bothered less and less by the ailment as she progresses through the rounds. Arn double-faulted on the last two points of the match, which lasted just 59 minutes.

Williams will play Ekaterina Makarova of Russia, who beat seventh-seeded Vera Zvonareva 7-6 (7), 6-1 earlier Saturday, in the fourth round on Monday.

Williams' next biggest threats to a sixth Australian title will be two Wimbledon champions - 2004 winner Maria Sharapova in the quarterfinals, and 2011 titlist Petra Kvitova in the semis.