MELBOURNE, Australia — Ana Ivanovic's hopes of a return trip to the Australian Open final fell apart in a barrage of mistakes Friday as Russia's Alisa Kleybanova ousted the 2008 runner-up with a 7-5, 6-7 (5), 6-2 victory in the third round.

With the 19-year-old Kleybanova constantly aggressive, fifth-ranked Ivanovic lost her serve nine times and finished with 50 unforced errors to just 23 winners.

When it was over, Kleybanova dropped to the ground on both knees, pumped her fists and blew kisses to the crowd. Ivanovic appeared to be nearly in tears as she walked off court, throwing a towel to someone in the crowd.

The Serb's loss came on a day that the late match between second-ranked Roger Federer against former No. 1 Marat Safat was supposed to produce the biggest news.

Instead, ethnic violence erupted between nationalist fans after Serbia's Novak Djokovic, the defending men's champion, beat Bosnian-born American Amer Delic.

One of several thrown chairs hit a woman and left her briefly unconscious. Insults and water bottles filled the air. Arrests were made, with dozens of people ejected from Melbourne Park.

This was what organizers had feared when they announced before the tournament that they were instituting a no-tolerance policy for disruptions.

They wanted the focus to remain on tennis — such as Kleybanova's upset victory, Andy Roddick's 22 aces while winning in straight sets or top-ranked Jelena Jankovic and No. 3 Dinara Safina advancing.

Instead of talking about how defending champion Djokovic reached the third round with a 6-2, 4-6, 6-3, 7-6 (4) victory packed with drama and good sportsmanship, the 21-year-old Serb and Delic were mostly quizzed about the chaotic scene that followed — when their supporters clashed outside near a big-screen TV showing the match.

Police said about 30 Bosnian and Serbian youths were ejected from Melbourne Park. Two men were charged with riotous behavior and a third was fined on the spot. The woman who was knocked out was not seriously injured.