Melbourne, January 23:

Pin-up Ana Ivanavic slumped out of the Australian Open but a flawless Roger Federer powered towards a 14th Grand Slam title as ethnic violence again overshadowed the tournament.

The fifth seeded Serbian tumbled to Russian teenager Alisa Kleybanova 7-5, 6-7 (5/7), 6-2, continuing her miserable run of form since winning the French Open last year. Her upset

came hot on the heels of American sixth seed Venus Williams being dumped on Thursday, throwing the season-opening Grand Slam wide open.

While Ivanovic flopped, fellow Serbs Novak Djokovic, the defending champion, and Jelena Jankovic, the women’s No 1, scrapped through. Federer floored fellow former champion Marat Safin in straight sets, hitting sparkling form as he overwhelmed his old rival 6-3, 6-2, 7-6 (7/5) to stay on course for a semi-final match-up with Djokovic.

Safin’s sister Dinara Safina continued to bulldozer through the draw while young guns Marin Cilic and Juan Martin del Potro set up an enticing fourth-round men’s match. Third seed Safina whipped Kaia Kanepi of Estonia 6-2, 6-2 and is in fine form after a breakthrough 2008, making good on her stated intention of playing a more aggressive game.

Top seed Jankovic was made to work against Japan’s Ai Sugiyama, 10 years her senior, before grinding out a 6-4, 6-4 win.

Also, Australia’s former World No 4 Jelena Dokic continued her fairytale comeback, beating Danish 11th seed Caroline Wozniacki 3-6, 6-1, 6-2.

But attention will inevitably focus on the violent clashes which followed Djokovic’s four-set win over Bosnian-American Amer Delic. Dozens of Bosnian and Serb youths hurled plastic chairs and other missiles at each other, leaving one woman with minor injuries. About 30 people were thrown out as skirmishes continued outside. A male streaker also invaded one court and danced around, naked from the waist down, in another security lapse.

Friday’s incidents took the gloss off Djokovic’s hard-fought 6-2, 4-6, 6-3, 7-6 (7/4) victory. While Djokovic went through, Spanish 11th seed David Ferrer crashed out to Croatia’s Cilic

7-6 (7/5), 6-3, 6-4. Cilic will now meet dangerous Argentine eighth seed del Potro who came from a set down to eliminat Luxembourg’s Gilles Muller 6-7 (5/7),

7-5, 6-3, 7-5.