MELBOURNE (AFP) – A flawless Roger Federer powered towards a 14th Grand Slam title at the Australian Open on Friday as ethnic violence again overshadowed the tournament.

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 Serb third seed Novak Djokovic.
“It's special to play Marat, we go way back. I think we like playing each other. It doesn't matter who wins, it is always a good contest,” said the Swiss great.
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 number of people got into a chair-throwing contest between two groups with the result that 30-odd people were ejected from Rod Laver,” said Inspector Chris Duthie of Melbourne East Police.
“We're charging two on summons and one will be receiving an on-the-spot fine.”
A male streaker also invaded one court and danced around, naked from the waist down, in another security lapse.
The Australian Open was first marred by violence in 2007, when Serbian and Croatian fans attacked each other with flagpoles, bottles and boots.
Then last year, police used pepper spray to subdue rowdy elements watching a match between Konstantinos Economidis of Greece and Chile's Fernando Gonzales.
Friday's incidents took the gloss off Djokovic's hard-fought 6-2, 4-6, 6-3, 7-6 (7/4) victory.
“I'm really sad to hear about it,” said Delic when told of the violence.
“As I said a couple of days ago, there's absolutely no place for that here. This is a tennis match.”
While Djokovic went through, Spain's 11th seed David Ferrer crashed out to Croatia's Marin Cilic 7-6 (7/5), 6-3, 6-4.
Cilic will now meet dangerous Argentine eighth seed Juan Martin del Potro who came from a set down to beat Luxembourg's Gilles Muller 6-7 (5/7), 7-5, 6-3, 7-5.