The 36-year-old, who was targeting a record-equalling 24th Grand Slam singles title at Flushing Meadows, angrily confronted umpire Carlos Ramos after being told off for what he deemed a coaching intervention.
Serena stormed up to his chair and informed him that she would never deliberately receive guidance from her coach, Patrick Mouratoglou, who was sat in the players' box.
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Serena Williams's coach Patrick Mouratoglou

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She informed Ramos in strong terms:
I don't cheat to win! I'd rather lose... I'm just letting you know!
Williams was clearly still fuming as she sat at the changeover at 2-1 up in the second set, before getting a point docked for hurling her racket to the ground, and then launching a series of tirades at the umpire, who sent her further into a rage when he handed her a game penalty for verbal abuse.
She followed that up by calling him a "thief" for taking a game away from her.

Serena Williams points at the umpire during her US Open final defeat against Naomi Osaka

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In a further exchange, Williams again informed umpire Ramos that she is not a cheat and did not receive coaching from Mouratoglou, even adding that she had a daughter so would not do that.
You owe me an apology. I have NEVER cheated in my life. I have a daughter and I stand for what is right and I have NEVER cheated.
The confrontation came at a time when Williams perhaps needed a spark after she lost the opening set 6-2 to the dominant Japanese starlet.

Serena Williams talks to the umpire during the US Open final

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The 20-year-old Osaka displayed an array of stunning groundstrokes in storming to a famous victory - Japan's first Grand Slam.
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