During Saturday's match, Williams was handed a coaching violation and a point penalty for breaking her racquet.
Serena Williams was fined $17,000 (£13,100) for the code violations that included calling the umpire a "liar" and "thief" in her US Open final loss.
The American star was fined for coaching, racquet abuse and for verbal abuse when she accused umpire Carlos Ramos of being "a thief" during the stormy final.
She was truly sad for Serena Williams, who was looking for her 24th Grand Slam, according to Tennis Now.
It all started when Carlos Ramos, the chair umpire, issued Williams a code violation for receiving illegal coaching from the sidelines.
The American appealed for calm in her runners-up speech, asking her supporters to "give credit" to Osaka's achievement, and the victor was then applauded.
"Everyone was cheering for her, I am sorry it had to end like this", Osaka said during the on-court trophy presentation.
"What the umpire did is totally not acceptable and I hope that we are going to have a sanction because we just can't let that happen", she said.
"Your question is making me emotional", she told a reporter during the post-match press conference.
Osaka's father, Leonard Francois, gets so nervous he can not watch his daughter in action, but she credits him for her big-match mentality.
This was not the way it was supposed to go for Williams, 36, perhaps the greatest player her sport has seen, on a night that was supposed to be a celebration of her career and her comeback to the top of tennis a year after giving birth.
Williams, who was under the impression the first violation had been rescinded, returned to Ramos to seek an apology for saying she had received coaching earlier. There's also the freakish "abuse" citation, which Ramos doled out because Williams called him a "thief" - certainly far from the worst thing an athlete has called an official during an event. While Williams was adamant that she never receives coaching, her coach, Patrick Mouratoglou, acknowledged afterward that he did try to signal Williams, but didn't think she had seen him. Williams argued the call and threatened the lineswoman that she would "shove this [expletive] ball down your [expletive] throat".
In the wake of Osaka's first Grand Slam triumph, there were messages of support for Williams as well as those condemning her behavior and agreeing with the umpire's calls.
Williams, meanwhile, though she still clearly feels wronged, isn't deluded about the outcome.
"Because the young player outplayed her in the first set, I think pressure got her more than anything". Williams told them the whole episode "is not fair", and said: "This has happened to me too many times". This is a grand slam final'.
In the rule book, verbal abuse is defined as "a statement about an official, opponent, sponsor, spectator, or other person that implies dishonesty or is derogatory, insulting or otherwise abusive".
Mouratoglou took to Twitter afterwards, hitting out at Ramos.
One thing that is certain is that Osaka's stock around the world, but particularly in Japan, will skyrocket.
Most of the sport's infamous brats have been men, and they have often been punished for bad behaviour.
With jeers bouncing off the arena's closed roof, both players - the champion, Osaka, and the runner-up, Williams - wiped away tears during a trophy ceremony that was awkward for everyone involved.
"If they can't adhere to the rules then they will have to allow the coaching because we can't have things like this outburst anymore".