Serena Williams Fights Tears, Walks Out of Presser After Loss to Naomi Osaka

Emotional moment for Serena Williams -- who choked back tears before abruptly ending a press conference after her loss to Naomi Osaka at the Australian Open.

The 39-year-old superstar was defeated by Osaka in straight sets in a semi-finals match Thursday morning -- and as she left the court, put her hand on her heart to show love for the Australian crowd.

During the post-game press conference, Serena was asked if the gesture meant she was saying "farewell" ... especially with all the retirement talk following her these days.

"I don't know," Serena responded ... "If I ever say farewell, I wouldn't tell anyone."

Moments later, Serena was asked about the unusual amount of unforced errors she committed during her match with Osaka ... was she injured or was it just a bad day at the office?

That's when Serena grabbed a sip of water, took a deep breath ... and seemed to fight back the tears.

With her voice shaking, Serena finally replied, "I don't know" ... and that's when she stood up and said, "I'm done" ... and walked off.

Obviously, she just lost a match she cared deeply about winning -- and she's understandably emotional. But, it's unclear if she's seriously considering retirement.

As for her opponent, Naomi Osaka did her post-game presser wearing a Lakers jacket in an apparent tribute to her former mentor, Kobe Bryant.