'It's a lifetime thing': Caroline Wozniacki reveals she suffers from rheumatoid arthritis

World number three Caroline Wozniacki said she hopes to become an inspiration for fellow sufferers of rheumatoid arthritis as her shock diagnosis drew support and sympathy on Friday.

The 28-year-old Dane revealed she was suffering from the condition after crashing out of the WTA Finals against Elina Svitolina late on Thursday, ending her title defense. The reigning Australian Open champion and former world number one has since received a flood of supportive messages and well wishes on social media.

Wozniacki was diagnosed with the autoimmune disease, which causes swelling of the joints and fatigue, before the US Open. She said she felt unwell after Wimbledon, before waking up during the Rogers Cup in August unable to lift her arms.

"I thought it was just the flu," she told journalists in Singapore. "After the US Open, I just kind of had to figure out what really was going on. So that's when I really figured it out. I went to see one of the best doctors there is and start treatment. In the beginning, it was a shock. You feel like you're the fittest athlete out there... and all of a sudden you have this to work with. It is what it is, and you just have to be positive."

Wozniacki said the illness required daily management, and that there were some days when she struggles to get out of bed. "It's a lifetime thing. It's not something that just goes away," she said. "You learn how to just cope after matches. Some days you wake up and you can't get out of bed and you just have to know that's how it is, but other days you're fine."

Having wrapped up her season, which included a breakthrough Grand Slam title in Melbourne, Wozniacki said she would now learn more about rheumatoid arthritis and how to manage it.

"I caught it somewhat early, so that's great," she said. "You find a plan, figure out what to do, do your research, and thankfully there are great things now that you can do about it."

Wozniacki hoped to become a role model for those with the condition. "I know there are a lot of people in the world that are fighting with this," she said. "Hopefully I can be someone they can look up to and say if I can do this, then they can too. And you just kind of have to get together and pull each other up."