It has undoubtedly been an unfortunate run-in for the season's first Grand Slam event.

The participation this year of Japan's enigmatic former world number one women's player, Naomi Osaka, has been uncertain given that she has not played an official match since September 2022.

Osaka clarified the doubts in conclusive fashion with a quirky tweet on January 11 offering "a little life update for 2023." 

She is pregnant and plans to take a break from tennis at least until next year.

In what will be the first Australian Open to be played since the retirement of four-times winner Serena Williams, another former women's world number one will be absent - Romania’s Simona Halep - currently seeking to clear her name after being provisionally suspended after testing positive for the banned stimulant Roxadustat during last year's US Open.

On the men's side, Spain's 19-year-old world number one Carlos Alcaraz, winner of the 2022 US Open, has had to give Melbourne a miss because of a leg injury. 

There is already a special link between him and the tournament as, aged 17, Alcaraz qualified for the Australian Open main draw, thus becoming the youngest participant in the men's singles.

And today there was an emotional press conference on site as Australia's very own mercurial talent Nick Kyrgios, currently ranked 21st in the world and a runner-up in last year’s Wimbledon men’s singles, explained how he had had to withdraw from his home tournament at the last minute because of an MRI scan showing up a knee problem which will require an operation next week.

But Kyrgios, for all his alternate brashness and brilliance, is not the biggest miss of the tournament for the hosts. That would be Ashleigh Barty.

It was on March 23 last year, a couple of months after earning her third Grand Slam in becoming the first home player to win the Australian Open title since 1978 that Barty - comfortably the world number one at the age of 25 - announced her retirement.

What?!

The tennis world whirled after she had delivered her news in an interview with her friend and former doubles partner Casey Dellacqua via her social media channels.

"Today is difficult and filled with emotion for me as I announce my retirement from tennis," Barty wrote in a post on Instagram, alongside a video of the interview.

"And... it's the first time I've actually said it out loud. It's hard to say. But I'm so happy, and I'm so ready. I just know at the moment, in my heart, for me as a person, this is right.

"I'm so grateful to everything that tennis has given me. It's given me all of my dreams, plus more. But I know that the time is right now, for me to step away and chase other dreams and put the rackets down."

Barty, who had previously won the French Open and Wimbledon titles, added that winning the latter "changed a lot for me as a person, to be able to win Wimbledon, the one true dream that I wanted in tennis."

She also said winning in her homeland felt like "the perfect way" to call it a day.

"Ash, what can I say, you know I have tears right?" tweeted Halep in response. "My friend, I will miss you on tour. You were different, and special, and we shared some amazing moments. What's next for you? Grand Slam champion in golf?"

The latter was a reference to Barty’s natural talent for any sport involving a ball and hand/eye co-ordination. 

She is an accomplished golfer and played professional cricket for more than a year during a mid-career hiatus.

Barty is not the first woman to retire at the top in tennis. 

In 2008, also at the age of 25, Belgium’s Justine Henin announced she was quitting the game, citing accumulated fatigue, in order to concentrate on her charity work and tennis school.

Henin made a return to the game 16 months later, reaching the 2010 Australian Open final after gaining entry on a wildcard before being beaten in three sets by Serena Williams.

But she retired for good in January 2011 because of an elbow injury. She gave birth to a girl in 2013 and a son four years later.

Henin’s Belgian compatriot Kim Clijsters was a notable high-achieving post-retiree in women’s tennis. 

She first called it a day in 2007, aged 23, having been world number one and won the US Open in 2005.

But after getting married and starting a family, she returned to the game in 2009 and won her second US Open title as an unseeded player in only her third tournament back.

She retained her title the following year, and added an Australian Open title in 2011, which put her back in the world number one position.

Meanwhile, Barty has made another public announcement, sharing news on social media that she and her husband, golfer Gary Kissick, are expecting a baby. 

"2023 set to be the best year yet," she said. "We are so excited for our new adventure."

After safely negotiating today's first round match against Germany's Julie Niemeier, the 21-year-old Polish player who has taken on the role of women’s world number one in Barty’s absence, Iga Świątek, paid tribute to the non-defending champion.

"Last year when I lost against her in Adelaide I had to do everything to learn to get back this slice," Świątek said. 

"For the next few months I was really motivated. I'm really grateful - her tennis is amazing and she pushed us to our limits.

"She is a huge inspiration and the way she behaves, she is really classy. It just seemed she really likes competing and having a challenge. She inspired me to work on myself."

So Australia's former world number one now knows she has helped her successor become an even stronger player…

Will Barty stay away from the party? Will she return in the manner of Henin and Clijsters? Or will she head off towards the greens or the cricket pitch?

Time will tell - but right now, no doubt, Barty would insist she has started a new party of her own.