Injured Azarenka adds to Toronto withdrawals August 5, 2013 -- Updated 1847 GMT (0247 HKT) Victoria Azarenka takes a drink during the final of the WTA Carlsbad tournament which she lost to Samantha Stosur. Victoria Azarenka pulls out of WTA tournament in Toronto Two-time Australian Open winner has a back injury She lost in the final of Carlsbad tournament to Samantha Stosur Montreal Masters starts Monday with Novak Djokovic cefending title (CNN) -- Australian Open champion Victoria Azarenka has joined the growing list of injury casualties at the WTA Rogers Cup tournament in Toronto. The Belarus star has moved to second in the world rankings, despite losing to Samantha Stosur in the final of the Carlsbad tournament in California. But after Sunday's straight sets defeat Azarenka pulled the plug on her appearance at the prestigious hard court tournament in Canada, citing a lower back injury. "I'm so disappointed that I can't make it to Toronto as I added it to my schedule knowing what an important event it is," Azarenka said in a statement. I am sorry to all my Canadian fans and I will work hard to get healthy and back on the courts as soon as possible. Azarenka had only just recovered from the knee injury which forced her out of Wimbledon after the first round. Read: Sharapova pulls out of Rogers Cup Maria Sharapova, who also sustained an injury in the second grand slam of the season, was an earlier withdrawal from the Toronto event. It will leave both of them short of match practice on hard courts ahead of the final grand slam of the season at Flushing Meadows for the U.S. Open. Britain's rising young star Laura Robson joined them on the sidelines before hitting a ball. The World No.32 pulled out ahead of a first round match against Belgian Yanina Wickmayer with a wrist injury. Azarenka's withdrawal has meant she will be replaced in the draw by former World No.1 Caroline Wozniacki, with the Dane given a first round bye. World No.1 Serena Williams is top seed as she builds up to her defense of the U.S. Open title later this month. Meanwhile, the men's Montreal Masters also started Monday, with No.1 Novak Djokovic as defending champion and new Wimbledon champion Andy Murray as his main challenger. First day action saw Germany's Florian Meyer beat Australia's Bernard Tomic 5-7 6-3 6-3 in a match between up and coming stars of the circuit. July 9, 2013 -- Updated 1111 GMT (1911 HKT) As Britain continues to celebrate Andy Murray's Wimbledon title, things aren't going quite as well for Roger Federer. July 5, 2013 -- Updated 1127 GMT (1927 HKT) The final game of one of the most memorable matches in Wimbledon history, featuring two fan favorites, took on a life of its own. June 20, 2013 -- Updated 0954 GMT (1754 HKT) When Andy Murray dedicated a tournament win to a friend, it revealed an unexpected personal side to one of the more guarded men in sport. June 19, 2013 -- Updated 1844 GMT (0244 HKT) Open Court sifts through the archive to bring you some of its favorite interviews from the past 3 years. June 19, 2013 -- Updated 1835 GMT (0235 HKT) Open Court's Pat Cash takes viewers for a behind the scenes tour of Wimbledon. June 7, 2013 -- Updated 2101 GMT (0501 HKT) For some of the biggest names in tennis, the French Open's red clay courts mean only heartbreak and shattered dreams. June 6, 2013 -- Updated 1105 GMT (1905 HKT) She drank alcohol on court, smoked "furiously" and horrified the establishment with her daring outfits and "unladylike" playing style. May 28, 2013 -- Updated 1445 GMT (2245 HKT) CNN's Open Court talks to the past five French Open women's champions ahead of the start of the tennis season's second grand slam tournament. June 2, 2013 -- Updated 1343 GMT (2143 HKT) CNN's Christina MacFarlane shows us what it takes to be an umpire at Roland Garros. May 21, 2013 -- Updated 0939 GMT (1739 HKT) Nicknamed the "kissing disease," mononucleosis or glandular fever is a viral illness that is affecting tennis stars. May 1, 2013 -- Updated 1129 GMT (1929 HKT) She towers above him, but she can't do without him. Meet the man who has made Maria Sharapova the world's wealthiest female athlete.