As she made her way off the court on Thursday at Rod Laver Arena, Serena Williams stopped for a moment as the recently returned crowd stood and showered her with applause. She raised her left arm to wave before moving her hand over her heart, as if to let them know the feeling was mutual. She paused for a moment, soaked in the ovation like the Melbourne late-summer sunshine and waved again before disappearing into the tunnel.

Her run at the 2021 Australian Open was over, ended in straight sets in the semifinals by her heir apparent, Naomi Osaka. And then, the questions started ... on television, social media and maybe even from your own couch: Was the match all that was over?

Less than an hour later, while sitting in front of dozens of members of the media in person and others around the world on computers, Williams was asked if the on-court moment was a goodbye, of sorts.

"I don't know," she said in her news conference. "If I ever say farewell, I wouldn't tell anyone."

She smiled, but it faded quickly. As the next reporter started to ask an innocuous question around the uncharacteristic amount of unforced errors Williams had in the match, she tried to fight back tears by drinking water, looking down or shielding her eyes with her visor. Her voice cracked when she started to answer.

"I don't know," she said, before abruptly standing up and stating, "I'm done."

Williams was gone again, leaving behind more questions than answers.

While Williams herself has given no concrete indication of an impending retirement, the 39-year-old's time in the sport is inevitably nearing some kind of end. And whether this truly was the last time we see Williams at the Australian Open or if she plays for several more years, the sport is better because of her, as evidenced in part by Osaka herself.

It seemed liked everything was coming together for Williams this fortnight. She had been playing arguably her best tennis since returning from maternity leave in 2018 and was heading into the tournament injury-free, having recovered from a lingering Achilles tendon injury, which had forced her to withdraw at the pandemic-delayed French Open in September.

Williams held off the powerful Aryna Sabalenka in three sets in the fourth round in Melbourne. She had dismantled World No. 2 Simona Halep, who had defeated Williams in the 2019 Wimbledon final, in the quarterfinals.

Having won seven titles in Melbourne -- including her most recent in 2017 while pregnant with her daughter, Olympia -- the city and tournament hold a special place in Williams' heart, and it seemed like the perfect place to make history. The winner of 23 major titles, she has been one away from tying Margaret Court's long-standing record since that 2018 return and has come oh-so-close -- reaching four Grand Slam finals and two semifinals during that span.

For this latest opportunity, Williams had to again get past Osaka. The 23-year-old had won their previous major meeting in their famous 2018 US Open final, and it was serendipitous for Williams to have another chance against Osaka with so much on the line. In a battle of the Greatest of All Time against the Greatest of Right Now, Williams wanted to prove she was still both.

But Osaka out Serena-ed Serena, simply better in all the ways Williams has for so long dominated tennis. Osaka had six aces (to Williams' three) and an 85% first-serve win rate, won all four of her break points and recorded 20 blistering winners. After a nerve-filled opening two games, where she struggled with her ball toss, Osaka never again opened the door for Williams.

Osaka advanced to her fourth major final, where she will take on American Jennifer Brady and look to improve to a perfect 4-0 when playing on the biggest stage. Since her first win at the 2018 US Open, Osaka -- representing Japan but raised and based in the United States -- has risen up the ranks and become one of the most visible athletes in the world. Like so many, she has her American counterpart Williams to thank for that.

Osaka's father now somewhat famously started her and her sister in tennis due to the success of Williams and her sister Venus. He followed the blueprint set by Richard Williams and put rackets into the hands of his two young daughters.

"My young aspirations owe so much to Serena and Venus," Osaka wrote in a column for The Telegraph last month. "Without those trailblazers, there would be no Naomi, no Coco [Gauff], no Sloane [Stephens], no Madison [Keys]. Everything we did was inspired by them, and my sister and I would dream about one day playing them in a Grand Slam final."

The Williams sisters' success motivated many to play a sport they might not have otherwise considered. At the 2020 US Open, there were a record 12 Black women, nearly 10% of the field, in the singles draw. Teenager Robin Montgomery was among the group, and she didn't hesitate in discussing the influence the sisters' had on her life when talking to ESPN before the tournament.

"Of course, Serena and Venus have been my role models since I was young," she said. "My goal is to have the chance to inspire the younger generations the way Serena and Venus were able to inspire my generation and so many other generations."

Throughout her storied career, Serena Williams has been so much more than "just" a tennis player. She is a single-named pop culture icon, celebrated businesswoman, frequent magazine cover story star and powerful advocate for racial and gender equality. Osaka has followed the path Williams paved, while finding her own voice and identity.

Williams' legacy is about far more than trophies and records and aces, although those have been impressive. It should hardly be surprising when we watch Osaka discuss gender equality during a postmatch news conference, as she did Thursday; she isn't afraid to take a stand, because she has seen it been done countless times before.

Osaka will look to add to her trophy case on Saturday as she vies for her fourth career Grand Slam title. Williams will have to wait for her next chance to win another, if she plans on continuing to play. Williams took to Instagram later on Thursday, posting a picture of herself wearing one of her signature Nike T-shirts and standing with her arms outstretched alongside a note to the Australian fans.

"I am so honored to be able to play in front of you all," part of her post said. "Your support -- your cheers, I only wish I could have done better for you today. I am forever in debt and grateful to each and every single one of you. I love you. I love you. I love you. I adore you."

Many will undoubtedly speculate about the post and Thursday's events, but it will be up to Williams alone to decide when the time has come to walk away. She more than deserves that. But when asked about the eventual end of Williams' legendary career, Osaka seemed to speak for all of Williams' fans.

"It's kind of sad when you say it like that because, for me, I want her to play forever," she said. "That's the little kid in me."