Serena Williams out of Australian Open

MELBOURNE, Jan. 23 (UPI) -- Five-time champion Serena Williams was upset by unseeded Ekaterina Makarova Monday in the fourth round of the Australian Open.

The 56th-ranked Makarova bounced the American superstar 6-2, 6-3 in a match that lasted 82 minutes in blistering heat at Melbourne.

Williams, who was hampered by an ankle injury sustained during the tuneup even in Brisbane, committed 37 unforced errors against the Russian, who advanced to her first Grand Slam quarterfinal.

Makarova moved on to play the winner of Monday's match between compatriot Maria Sharapova and Germany's Sabine Lisicki.