Tomic can be top five in tennis: Raonic Big-serving Canadian Milos Raonic believes Bernard Tomic has the potential to become one of the world's best tennis players, but only if the Australian keeps his focus squarely on improving his game. Tomic's career has stalled somewhat since breaking into the world's top 50 as an 18-year-old in 2011. Currently ranked 51st in the world, Tomic is desperate to make a rapid rise up the ranks in 2014 and to put the off court issues that dogged his 2013 campaing behind him. Raonic, who boasts one of the fastest serves in world tennis, also enjoyed a breakthrough campaign in 2011. But unlike Tomic, the soon-to-be 23-year-old has gone on with the job, reaching a career-high ranking of No.10 in August. The pair will lock horns on Saturday night when Australia face off against Canada on day one at the mixed-teams Hopman Cup in Perth. Raonic knows Tomic well from their junior days, and says the 21-year-old has the potential to break into the world's top five if he sets his mind to it. "Knowing Bernie and what he's capable of and how talented he is, I think he can go very far," Raonic said in Perth on Thursday. But it's all about improving. You can't focus on the moment right now. You have to look at the big picture and make sure every week, every month and every year you're getting better. People say to me my serve can get me there, but you've got to keep developing. Tomic will team with 2011 US Open champion Samantha Stosur at Hopman Cup XVI, while Raonic has been paired with rising star Eugenie Bouchard for the fourth-seeded Canadians. Top seeds Poland were dealt a blow earlier this month when world No.21 Jerzy Janowicz was forced to withdraw due to a foot injury. He has been replaced by world No.288 Grzegorz Panfil, who will team with world No.5 Agnieszka Radwanska.