'It's been a fun ride': Serena Williams bows out of US Open

Serena Williams bid an emotional good-bye to the US Open following a third-round defeat to Ajla Tomljanovic, in what could be the last singles match of her glittering career.

Serena enjoyed a good start to the major, registering a second-round win over world number two Anett Kontaveit. But she fell short against the 46th ranked Australian, losing 7-5, 6-7 (4), 6-1.

The 40-year-old, who last month signalled she planned to retire after the US Open, lost after a gruelling battle that lasted three hours and five minutes.

Serena, who amassed 23 Grand Slam singles titles in her 27-year career, poured everything into one last stand in front of a partisan crowd at the Arthur Ashe Stadium.

But the veteran wilted in the decisive third set, affected by the demands of a heroic second set display that saw her level the match in a tie break.

As Tomljanovic raced into a 5-1 lead in the third, Serena continued to fight, saving five match points in a marathon seventh game before finally succumbing.

Afterwards Serena thanked the crowd. Asked by an on-court interviewer whether there was any possibility she might yet extend her career, she replied: "I don't think so, but you never know."

Congrats on an amazing career, @SerenaWilliams!How lucky were we to be able to watch a young girl from Compton grow up to become one of the greatest athletes of all time.I'm proud of you, my friend—and I can't wait to see the lives you continue to transform with your talents. pic.twitter.com/VWONEMAwz3

"It's been a fun ride," she said. "It's been the most incredible ride and journey I've ever been on, I mean, in my life.

"I'm just so grateful to every single person that's ever said, 'Go, Serena,' in their life. I'm just so grateful. You got me here."

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