'I'm so ready' - Emotional Ashleigh Barty announces retirement from tennis at 25 and as World No. 1

"I'm so happy and I'm so ready. And I just know at the moment in my heart, for me as a person, this is right," Ashleigh Barty said as she announced her shock retirement at the age of just 25 on Wednesday. "I wasn't sure how to share this news with you so I asked my good friend [retired Australian tennis player Casey Dellacqua] to help me. I am so thankful for everything this sport has given me."