NEW YORK (Reuters) - Naomi Osaka became Japan’s first Grand Slam singles champion by thumping Serena Williams 6-2 6-4 in a controversial U.S. Open final on Saturday in which the American suffering a mesmerizing meltdown after being given a code violation.

It was drama-filled conclusion to a match rich with storylines that will go down as one of the most controversial Grand Slam finals of all time.

There was much riding on the outcome for both players, with Osaka bidding to become the first man or woman from Japan to lift a Grand Slam singles title and Williams trying to equal Margaret Court’s record of 24 major titles.

In the end, it was Osaka making history but on a day of bizarre events her victory will only be a footnote to what is sure to go down as one of the most infamous matches ever played at Flushing Meadows.

With Osaka in control of the contest after taking the first set, Ramos sent Williams into a rage when he handed the 23-times Grand Slam champion a code violation in the second game of the second set after he spotted the American’s coach Patrick Mouratoglou making hand signals from the player’s box.

A string of incidents followed as Williams went on to incur a point penalty for smashing her racket after Osaka broke her to get back on serve at 3-2.

Williams was then hit with a game penalty at 4-3 after she launched into a verbal attack against Ramos, accusing him of being “a liar” and “a thief for stealing a point from me”.

The game penalty put Osaka 5-3 up and the 20-year-old Japanese kept her cool to close out the win.

The chaotic finish filled with screaming, tears and jeers cast a cloud over what should have been Osaka’s shining moment.

Standing on the podium waiting to be handed her trophy and a winner’s cheque for $3.8 million, Osaka heard only boos as an angry crowd took out their frustration on Portuguese chair umpire Carlos Ramos, who stood to the side.

“I know everyone was cheering for her and I’m sorry it had to end like this,” Osaka said. “It was always my dream to play Serena in the U.S. Open finals.”

Rarely do matches get to the point where a chair umpires hands out a game penalty.

The USTA said it was unaware if any other such sanctions were awarded during the U.S. Open fortnight.

In a timeline the USTA detailed events of the women’s final and indicated Ramos was right to make the calls he did and on Sunday the ruling body fined Williams $17,000 for the three Code violations.

Mouratoglou later admitted he had been coaching but in another strange twist an unrepentant Williams continued to deny she had received any advice and was instead a victim of sexism.

When approached for comment from Ramos the USTA said it does not make umpires available to the media.

“He (Ramos) alleged that I was cheating, and I wasn’t cheating,” said Williams. “I’ve seen other men call other umpires several things.

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“I’m here fighting for women’s rights and for women’s equality and for all kinds of stuff.

“For me to say ‘thief’ and for him to take a game, it made me feel like it was a sexist remark.”

FEARLESS DISPLAY

Almost lost in the chaos was a fearless and cool display from Osaka.

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Before Williams’s collapse, Osaka had already put the 36-year-old under rarely seen pressure.

Osaka had given Williams plenty of respect but no other concessions as she grabbed the early break on a double fault by her idol for a 2-1 first set lead she would not let go.

Playing on tennis’s biggest stage in her first Grand Slam final, the enormity of the moment did not faze Osaka while Williams, contesting her 31st major final, looked unsteady.

Williams’s implosion was not a totally unfamiliar sight for tennis fans, who watched a similar meltdown nine years earlier on Arthur Ashe Stadium.

Playing a semi-final against Kim Clijsters, Williams flew into a rage after a line judge called her for a foot-fault on a second serve, leaving her match point down to the Belgian.

Williams launched into an expletive-laced rant at the official. She waved her racket in the lineswoman’s direction and shook a ball in her clenched fist as she threatened to “shove it down” her throat.

She was initially fined $10,500 for unsportsmanlike behavior, the maximum allowed on site at a tournament, and was then slapped with an additional $164,500 fine and put on probation for two years by the Grand Slam Committee.

Williams could face further sanctions for her actions, the WTA issuing a statement to say it will be looking into the incident.

“There are matters that need to be looked into that took place during the match,” the WTA said. “For tonight, it is time to celebrate these two amazing players, both of whom have great integrity.”

Williams, however, received plenty of support from the tennis world including former American great Billie Jean King after whom the National Tennis Center is named and who has long fought for women’s equality in sport.

“When a woman is emotional, she’s “hysterical” and she’s penalized for it,” King said on Twitter. “When a man does the same, he’s “outspoken” & and there are no repercussions.

“Thank you, @serenawilliams, for calling out this double standard. More voices are needed to do the same.”