Ash Barty's surprising retirement shocks the tennis world on Twitter

World No. 1 Ash Barty announces retirement at age 25 (2:57)

Women's No. 1 Ash Barty announces her retirement, sitting down with longtime friend Casey Dellacqua to discuss her reasons and happiness in walking away. (2:57)

Ash Barty, the No. 1-ranked women's tennis player in the world, announced her retirement on Tuesday.

This is a shocking turn of events for tennis. Barty, only 25 years old, is at the top of her game -- she's less than two months removed from winning her home Australian Open, her third overall Grand Slam singles title -- the other two being the 2019 French Open on clay and 2021 Wimbledon on grass.

Barty has held the world No. 1 ranking for 114 consecutive weeks, according to the WTA Tour.

"I don't have the physical drive, the emotional want and everything it takes to challenge yourself at the very top of the level anymore," Barty said in an Instagram video interview explaining her surprising decision. "I am spent."

Barty is only the second woman to retire with the world No. 1 ranking -- the other being Justine Henin, who also decided to step back at the age of 25, in 2008.

The news sent shock waves through the sports world, with Barty's friends and competitors sending her well-wishes despite their disbelief.