Serena Williams announces she is on 'countdown' to retirement

US great Serena Williams announced on Tuesday that "the countdown has begun" to her retirement from tennis.

"There comes a time in life when we have to decide to move in a different direction," the 23-time Grand Slam winner said in a post on Instagram.

"That time is always hard when you love something so much. My goodness do I enjoy tennis. But now, the countdown has begun.

"I have to focus on being a mom, my spiritual goals and finally discovering a different, but just exciting Serena. I'm gonna relish these next few weeks."

On Monday, Williams played only her second singles match since she returned to action at Wimbledon in June after a year-long absence from competition, beating Spain's Nuria Parrizas Diaz to reach the second round of the Toronto Open.

But the 40-year-old said after that match that she could see the light at the end of the tunnel before suggesting the US Open starting this month could be her swansong.

"I have never liked the word retirement," Williams wrote in a Vogue article on Tuesday. "It doesn't feel like a modern word to me. Maybe the best word to describe what I'm up to is evolution. I'm here to tell you that I'm evolving away from tennis, toward other things that are important to me.

"A few years ago I quietly started Serena Ventures, a venture capital firm. Soon after that, I started a family. I want to grow that family."

A post shared by Serena Williams (@serenawilliams)

Williams won her last Grand Slam in 2017 and has been chasing an elusive 24th crown that would draw her level with Margaret Court, who holds the record for most majors. She came close to achieving that feat, featuring in four major finals since giving birth to daughter Olympia in 2017.

Explaining her decision to move away