The 36-year-old, who was targeting a record-equalling 24th Grand Slam singles title at Flushing Meadows, angrily confronted umpire Ramos after being told off for what he deemed a coaching intervention. "I have a daughter and I stand for what's right for her".
The American star was fined for coaching, racquet abuse and for verbal abuse when she accused umpire Carlos Ramos of being "a thief" during Saturday's stormy final.
Serena Williams was given a second violation, this one for smashing her racket, and again yelled at the chair umpire who had given her a first warning for coaching.
A tearful Serena Williams has said she will continue to fight for women's rights after claiming she had no regrets about her ugly fight with umpire Carlos Ramos over cheating claims in the US Open women's final.
Richard Ings, a former rules and competition chief for the ATP, defended Ramos and called on the sport's governing bodies to support him.
Tennis legend Chris Evert tweeted that Ramos should have warned Williams about the verbal abuse violation before penalizing her.
After her next service game, she argued with officials in the corner again, saying that she was targeted every year by umpires at the U.S. Open.
That was the tipping point and Osaka wrapped up the win in one hour, 26 minutes with a service victor, breaking into a smile as the ball flew off the frame of Keys' racquet and into the crowd.
"She's always working to improve; always eager to embrace new challenges; and to set new standards".
Two breaks of serve ensured that she assumed the early advantage, but the opening set was the calm before the storm as Williams exploded. "I'd rather lose. I'm just letting you know!" "This has happened to me too many times".
But her triumph was reduced to nearly a side note as Williams railed about her treatment, accusing the US Open of being out to get her. We're gonna get through this, and let's be positive. "So congratulations, Naomi. No more booing".
Before Saturday's match, Serena played Magda Linette and also beat Carina Witthoft from Germany, before eventually playing against her sister, Venus, in the third round.
This was a powerful example of emotional intelligence in real life.
"For me it blows my mind.This is outrageous".
Osaka reflected on the moment after the match when she returned to her seat and put a towel over her head as the ceremonial stage was being assembled.
On-court outbursts are another fairly frequent violation in tennis and it's unfortunate that this one was compounded by the first, which was out of Williams' hands to begin with.
It just wasn't against her opponent.
Serena Williams and Naomi Osaka will play the U.S. Open women's final with the roof closed at Arthur Ashe Stadium. While Williams was insistent that a male tennis player wouldn't have been penalized quite as harshly, she ultimately asked the crowd to calm down and let Osaka have her moment.