'Won't be back': Tennis icon's stunning call on Serena Williams

Australian Open fans have seen the last of Serena Williams, according to respected tennis commentator Sam Smith.

Speculation around the 23-time grand slam champions future has intensified after she was thumped in straight sets by Naomi Osaka in their semi-final at Melbourne Park.

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Williams gave a solemn and prolonged goodbye to fans after the match in a gesture that many took as her final farewell.

She then broke down and left during her press conference a little while later, adding fuel to the theory that it was her last Australian Open.

While the 39-year-old admitted that she wouldn't tell anyone even if it was the last time she'd grace the courts of Melbourne Park, Smith said she saw enough signs from the tennis star to tell her that the end was close.

"I've never seen her do that ever in 20 years," Smith told Nine's Weekend Today this morning.

"But I also know that both Serena and Venus are the most impossible athletes to predict, I've been following them since they were teenagers and you just never know with them which turn they're going to take and they wrong-foot you at every occasion.

"My gut feeling is that she won't be back and she'll play Wimbledon and US Open if, fingers crossed, they're on, and give that a really good ride."

Smith's prediction would give Williams three more chances to equal Margaret Court's all-time record of 24 grand slam titles, however, the commentator said she wouldn't be surprised if the American sits out the French Open on her least favoured clay surface.

Speaking on Wide World of Sports' The Morning Serve, former Aussie player Alicia Molik said she thought Serena broke down at her press conference because of the realisation that she simply couldn't compete with Osaka on the court.

"I think some of the tears in the press conference [on Thursday] were due to the fact that she was outclassed and beaten and the amount of times Serena Williams has had a match snatched away from her because someone has been too good is very rare.

Tennis analyst Matt Roberts also posed a similar theory on the Tennis Podcast, insisting that Serena simply wasn't allowed to dictate terms as she normally does, because of how good Osaka was.

Concerning signs for 23-time major winner

“We didn’t see the best of Serena but we did see the best of Naomi Osaka,” Roberts said.

“It’s brought out a question of was Serena playing badly by her standards because she was playing badly? Or was it because of what Osaka was doing to her?

“That is the thing I was wrestling with throughout the match and by the end I came down on the side of, it was what Osaka was doing more than anything that was causing Serena to have an off day.

“The pressure Osaka can apply to Serena is unlike what anyone else can do.

“She’s calling the shots against Serena Williams, which is an extraordinary thing to say and to witness.

“When you’ve spent your whole career knowing that your best is the best and feeling that way when you take to the court, when that doesn’t happen, that must shake you.

“I can imagine that her assessment of the match is therefore, in the immediate aftermath, a little bit compromised. She must be confused about what happened.

Smith said such theories merely lend weight to the idea that Williams knows in her heart that retirement is close.

"There's not that many times that Serena has been beaten (like she was against Osaka)," Smith said.

"And she was roundly beaten in that semi-final, by a better player. Normally if Serena loses it's because she's been a little bit off.

"And she knows, it's not just Osaka, Barty's going to improve, you've got (tonight's other finalist Jennifer) Brady coming up, there's Coco Gauff, there's a lot of very good young players."

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