Australia's Samantha Stosur easily beat Roberta Vinci -- the conqueror of world number one Caroline Wozniacki -- 6-4, 6-1 on Friday to reach the semi-finals of the $2.05 million WTA Rogers Cup. Stosur broke Italian Vinci's serve while leading 5-4 in the first set to take the opening set at the Rexall Centre facility. The Aussie then stepped up her game in the second set and moved through to the semi-finals with authority. "As the match went on, I obviously probably grew in confidence, and then you get that bit of a lead with a buffer of a couple breaks and felt like I could maybe start going for a bit more," Stosur said. "I went for some big ones and it paid off." Stosur next faces Poland's Agnieszka Radwanska, who beat German Andrea Petkovic 6-4, 6-3. "Semi-finals, you've got to believe that anything in possible," Stosur said. "Having said that, from semi-finals to winning the tournament, there's a still a long way to go, but I think in this position you've got to. If you don't, then it's probably a little bit silly." In other matches, fourth-seeded Victoria Azarenka of Belarus, the highest seeded player left in the event, made quick work of Kazakhstan qualifier Galina Voskoboeva, winning 6-1, 6-2. Voskoboeva leaves with her head high as she earned the title giant killer at this tournament after upsetting No. 9 Marion Bartoli, No. 25 Flavia Pennetta and former US Open winner Maria Sharapova to earn her spot in the quarter-finals. Azarenka will next meet either Serena Williams or Lucia Safarova for a place in the final.