Ivanovic beats Serena Williams
Ana Ivanovic moves on (AAP)
Ana Ivanovic has beaten Five-time champion Serena Williams at the Australian Open.
The Serbian lost the first set before coming back to beat Williams 4-6, 6-3, 6-3.
Williams hadn't lost a match since August, one of only four defeats in 2013, and came into the fourth round with 25 straight wins. It was her 70th match at Melbourne Park, a record in the Open era, and she set the mark for most match wins ever at the Australian Open with her third-round victory.
Ivanovic hadn't taken a set off Willliams in their previous four matches.
Two-time finalist Li Na wrapped up a fourth-round win over No. 22 Ekaterina Makarova in less than an hour to set up a quarterfinal against Flavia Pennetta.
The 2011 French Open champion broke Makarova's serve five times and fended off four break points on her own serve during a 59-minute, 6-2, 6-0 win to reach the quarterfinals here for the fourth time in five years.
Pennetta's late-career revival continued as she reached her first Australian Open quarterfinal with a 6-1, 4-6, 7-5 win over ninth-seeded Angelique Kerber of Germany.
The 28th-seeded Pennetta has played some of her best tennis since returning last February from a wrist injury that caused her ranking to drop as low as No. 166.
Li and Pennetta both turn 32 next month, one day apart.
"You know what, at least she is one day older than me. So I will play an older player," Li, who had back-to-back wins over the two youngest players in the tournament tin the first two rounds, joked in an on-court interview.
"Not like couple rounds (before), always younger than me. Nobody talked about the age."
Pennetta reached her first Grand Slam semifinal at the U.S. Open last year and has followed that by reaching her first quarterfinal at Melbourne Park in 11 appearances.
"I'm a little old so I'm starting to enjoy (tennis) more," she said.
"When you are young you want to win so much."
Pennetta broke Kerber to take a 5-3 lead in the third set but tightened up as she was serving for the match, giving the break right back. She recovered, however, to take a 6-5 lead and then broke Kerber to close out the match.