Australia captain Sam Stosur says her team is capable of upsetting Kazakhstan in their Billie Jean King Cup qualifier starting in Brisbane on Thursday. To reach the finals later this year, Australia needs to finish on top of their three-nation group, which also includes Colombia. World number 61 Kim Birrell is Australia's top-ranked singles player in the team, while Kazakhstan is led by 2022 Wimbledon champion Elena Rybakina. The Aussies are seeded fourth in this year's event after a quarterfinal loss to eventual runners-up Slovakia last year, while the Kazakhs are ranked 12th. But the official team rankings are based on performances over a four-year period, with recent results carrying more weight. Non-playing captain Stosur said home-court advantage and a team-first mentality could help her squad pull off an upset. "This team does get behind each other no matter what and you can create enormous upsets in this competition as we've seen over many years," she said. Kazakhstan's second singles player is 23rd-ranked three-time major quarterfinalist Yulia Putintseva, but Australia also boasts a three-time grand slam quarterfinalist in Ajla Tomljanović. Tomljanović is making her way back from injuries and has climbed back to 79th in the WTA rankings — her highest mark since August 2023, which was just a few months after she reached a career-high of 32 after a strong 2022 season. The 31-year-old said playing in the team event is the highlight of her year because nothing compared to representing her country. "Probably the toughest and most rewarding week in our calendar year," she said. "Olympics and Billie Jean King Cup has been the highlight of my career, just the feelings I get when I step on the court … nerves, but also being proud to be there." After Thursday's tie of two singles and one doubles match, Kazakhstan meets Colombia on Friday, with Australia meeting the South Americans on Saturday at the Queensland Tennis Centre. Colombia is a heavy underdog in the group, especially after its only players in the WTA top 600 — 53rd-ranked Camila Osorio and world number 84 Emiliana Arango — pulled out. The winners from the six groups playing around the world over the next four days will go through to a knockout round of eight in Shenzhen featuring defending champions Italy and hosts China.