Daria Saville's worst fears were confirmed this week when she was told she had suffered an ACL injury.

The Australian was forced to withdraw from her latest match against Naomi Osaka at the Pan Pacific Open after collapsing in serious pain.

She retired from the tournament after just seven minutes, unable to continue playing on her knee.

What did Saville say?

Saville took to Twitter to keep her supporters updated on her injury status. The timeline of her posts are truly heartbreaking to read as she now prepares for a lengthy spell away from the court to recover.

"Can we all pray it’s not [an] ACL, getting [an] MRI tomorrow," she wrote in the first tweet along with a crying emoji.

She followed up a few hours later with: "I’m seriously in disbelief… what the actual f happened… I am not even sad, I’m just shocked."

Saville has a history of ACL injury, so the nature in which she was forced off the court in Tokyo was immediately cause for concern.

The world number 55 underwent surgery on her knee in 2013 and finished the year ranked 144th in the world.

Her third post was a short and emotionless update confirming the nightmare of yet another serious injury had started.

"Torn ACL. 2013 flashbacks," Saville wrote in the early hours of Wednesday morning.

Who has shown support for Saville?

There was an immediate outpour of support from Saville's fans and fellow WTA Tour professionals.

World number one Iga Swiatek replied to one of her earlier tweets telling her to "get well soon" while Elise Mertens wished Saville a "speedy recovery."

Hundreds of other replies have armed Saville with the positivity to dive into her recovery head first and bounce back better than ever.

She followed up with a fourth tweet to acknowledge the support she has received and provide a further update on her mental state.

"Don’t worry about me by the way. I feel bad that everyone is so worried. I’m okay, I promise. It’s just s**t luck," she wrote.

On the other hand, US star Sloane Stephens has put a lighthearted spin on Saville's injury in an attempt to cheer her up.

"You’ll be back!!! If anyone can do it, it’s YOU!!! Can’t wait for your TikTok rehab," she wrote.

It took Saville nine months to recover from her previous injury, and in her first event following her rehabilitation, she won a doubles title alongside Storm Sanders in an ITF Circuit $50,000 event in Sacramento, California.