Australian Open tennis: Serena Williams breaks down in press conference

Serena Williams reacts during a press conference following her semifinal loss to Naomi Osaka at the Australian Open tennis championship in Melbourne. Photo / AP

Serena Williams sent the tennis world into a spin after breaking down into tears when asked about retirement following her semifinal loss to Naomi Osaka.

An emotional Williams spent an extended time on court waving to the crowd on Rod Laver Arena and bowing three times while clutching her hands up to her chest.

That gesture had the tennis world speculating the 39-year-old superstar may have played in Australia for the final time.

That speculation reached a frenzied level after her press conference when she was unable to answer a question about her future.

She attempted to sidestep the question before breaking down in tears when answering a follow-up question. She gave an apologetic gesture and walked out of the room, ending her press conference after less than four minutes. She did not return.

When asked if her special moment of applause from the Melbourne crowd was a farewell, she replied: "If I ever say farewell, I wouldn't tell anyone."

When asked about her error-riddled performance she said: "I don't know. I'm done."

She said earlier that it was her inexplicable unforced errors that separated her from Osaka.

"The difference today was errors. I made so many errors," she said.

"Honestly, there were opportunities where I could have been up 5-0 — and I just made so many errors.

Serena Williams leaves a press conference following her semifinal loss to Naomi Osaka. Photo / AP

"It was a big error day for me today."

She finished with 12 winners and 24 unforced errors.

This was arguably the greatest of all time falling apart like a local social tennis player who wore the wrong shoes.

Cheered on by her husband Alexis Ohanion, Williams looked lost, flustered and powerless.

Williams lost nine of the next 11 service games after having a break point opportunity to take a 3-0 lead.

Osaka went on to win the match 6-3 6-4.

Even screaming at herself after a rare winner to start the second set, Williams ultimately ended up being broken and falling behind again.

"Make the shot," she screamed into her chest as she clenched her fists.

Williams' body language suggested she knew she was beaten right then and there.

The fight went out of her at the back end of the second set and she gave up the last eight points of the match, gifting Osaka the easiest of opportunities to serve it out.

Naomi Osaka, left, is congratulated by Serena Williams after winning their semifinal match at the Australian Open tennis championship. Photo / AP

With crowds returning to the Aussie Open today

following Victoria's five-day lockdown, the cheers and applause quickly turned in favour of Williams as the crowd sensed Osaka was going to roll over the top of the American superstar.

The crowd extended Williams a farewell fitting of a champion as she returned their affection with an extended wave before walking up the players' tunnel into the uncertainty of 2021.

The time Williams spent waving to the crowd has led to speculation the 23-time grand slam champion may have played her final match in Australia.

Williams was all class as she said her goodbyes — and embraced Osaka at the net as the pair shared a private moment.

Williams can only have congratulated the Japanese star after a performance that ultimately outclassed Williams.

Osaka continued the classy sentiment in her on-court interview, saying it was an "dream" to play her former idol.

"I was just really, like, nervous and scared I think in the beginning. Then I sort of eased my way into it," she said.

"It's always an honour to play her. I just didn't want to go out like really bad, so I just wanted to try my best.

Serena Williams waves as she leaves Rod Laver Arena following her semifinal loss to Naomi Osaka. Photo / AP

"I don't know if there's any little kids out here today, but I was a little kid watching her play and just to be on the court playing against her for me is a dream."

Osaka was undeniably playing at a level that would have left any tennis player on Earth on the verge of breakdown - but this Serena defeat went both ways.

In the first set she had just four winners and 16 unforced errors.

One of the most brutal returners in the sport, Williams was rattling off groundstrokes that looked as ugly as they sounded.

According to Australian Open stats, Williams failed to return 30 per cent of Osaka's second serves — a stat tennis legend Jim Courier described as "inexcusable".

It wasn't until Osaka had the finish line in sight that Williams was gifted a look back into the match when Osaka had a mini-meltdown of her own with three double faults in the one service game, allowing Williams to level up at 4-4.

But Williams showed it simply wasn't her day when she was broken on the very next service game.

Osaka was simply too good, and now leads Williams 3-1 in their head-to-head.

She will play the winner of the Jennifer Brady-Karolina Muchova match in the final.

All of a sudden it is unclear if Williams will have a next match.