Roger Federer sails in Brisbane, Samantha Crawford crushes Andrea​ Petkovic

Sydney: Roger Federer took 55 minutes to dispel all injury doubts with a 6-2 6-1 routing of unheralded German Tobias Kamke in the second round of the Brisbane International on Thursday.

Media speculations swirled around the fitness of the world number three less than two weeks before he launches his bid for a fifth Australian Open title and the Swiss maestro dismissed them by dropping only three games in a lop-sided contest.

"I`m going to do my best to stay injury free and give myself a chance to win another grand slam," Federer said after setting up a quarter-final against Grigor Dimitrov.

Bulgaria`s Dimitrov came from behind to beat Viktor Troicki 5-7 7-6(6) 6-2, while big-serving Canadian Milos Raonic battled through to the last eight with a 6-7(2) 6-1 6-4 win over Croatian Ivan Dodig.

In the women`s draw, American qualifier Samantha Crawford continued her breakout run by storming into her first WTA semi-final after pummeling Andrea Petkovic.

The 20-year-old Atlanta native, ranked 142nd in the world, blasted 22 winners against the befuddled German in a 6-3 6-0 rout to further enhance her reputation.

"It happened fast. I was trying to not think about it too much, not psych myself out," the former U.S. Open junior champion said.

"Right after I won, on the on-court interview I was like shaking, and then in the locker room I was like sitting for just like a little bit.

"But yeah, this is awesome."

Crawford is playing in just her sixth WTA Tour event and her strong showing at an event which has seen the top seeds succumb to injuries should bring her inside the top 100 for the first time.

The American, who spent time growing up in China and speaks fluent Mandarin, has yet to drop a set in Brisbane after dispatching another rising talent Belinda Bencic of Switzerland in the second round.

She faces twice Australian Open champion Victoria Azarenka who trounced U.S. Open finalist Roberta Vinci 6-1 6-2.

Germany`s Angelique Kerber also booked a semi-final spot with a 6-4 6-4 victory against Russia`s Anastasia Pavlyuchenkova.

At number four, the German is the highest seed remaining after injury robbed the tournament of Maria Sharapova, Simona Halep and Garbine Muguruza.

In the last four, she takes on Spaniard Carla Suarez Navarro who rallied past American Varvara Lepchenko 4-6 6-4 7-5.