Ekaterina Makarova defeated five-time Australian Open champion Serena Williams 6-2, 6-3, in a loss Williams herself called "disastrous," Fox Sports reported.
Williams, who also suffered an ankle injury in Brisbane recently, did not put in enough practice time, and her game suffered for it, according to Fox Sports.
"I served like a . . . I guess that's not appropriate," Williams told Fox, rethinking her statement. "I can't even describe how I served, to be honest. It wasn't good enough. My lefty serve is actually better than that. Maybe I should have started serving lefty."
Williams refused to blame her loss on her injury, however. "I never blame any injury that I have because she played really well and deserved to win today," Williams, currently ranked No. 12 in the world, told Fox. "I look forward to our next match. I feel I can definitely play so much better. And that's good. Like if I felt I couldn't play better, that would be a problem."
Williams added that she was "obviously not a hundred percent. But it's no excuse or anything."
Makarova, ranked No. 56 in the world, could not be happier about her advancement in the Grand Slam. The strong lefty handed Williams some crucial down the line shots, securing her win.
"I played her in Beijing, and I was really afraid of her," Makarova told Fox. "It was really tough to play against her. But this time - I don't know - I felt so comfortable. I really thought I could beat her."
Fellow Russian powerhouse Maria Sharapova also advanced in the competition, defeating Sabine Lisicki 3-6, 6-2, 6-3, in a match lasting two-hours.
Makarova's win advances her to the quarter-finals of a grand slam for the first time. Last year, she made it to the fourth round at Melbourne Park but lost to Kim Clijsters, who won the championship.