The cheating controversy that pushed Serena Williams over the edge in the US Open final.

Naomi Osaka has became Japan’s first grand slam champion after she beat Serena Williams in a controversial US Open final.

The 6-2 6-4 victory appeared routine enough but the one hour and 19 minute match will be long remembered for a row between Williams and the chair umpire.

The headlines were supposed to be about the American’s bid for a record-equalling 24th grand slam title and Osaka trying to become Japan’s first slam winner, but instead an argument with umpire Carlos Ramos dominated the match.

Williams was furious when she was given a coaching violation early in the second set after a hand gesture from her coach Patrick Mouratoglou.

She was then docked a point for a second violation when she smashed her racquet after dropping serve at 3-3.

“I don’t cheat to win, I’d rather lose,” Williams told Ramos.

“I didn’t get coaching. You owe me an apology. I have never cheated in my life.”

???????????? This is so hard to watch

— Kimberley A. Martin (@ByKimberleyA) September 8, 2018

I have never seen anything like this in my life #USOpen18

— Maggie Gray (@MaggieGray) September 8, 2018

The crowd did not react well to the penalty against Serena Williams. #usopen pic.twitter.com/zIjVOZ9NfI

— Chris O’Leary (@olearychris) September 8, 2018

Naomi Osaka played an amazing match in the US Open final. And yes, she did outplay Serena Williams. I feel sorry for her that the crowd is not roaring and on its feet to congratulate her. It’s her first (but definitely not last) Grand Slam win. #UsOpen

— Juliet Macur (@JulietMacur) September 8, 2018

Serena Williams after receiving a coaching violation in the #USOpen final:

“I don’t cheat to win. I’d rather lose.” pic.twitter.com/ml8FOrecQy

— Complex Sports (@ComplexSports) September 8, 2018

She then received a game penalty for her outburst, putting Osaka within one game of winning.

“Are you kidding me? You will never, ever, ever be on another court of mine as long as you live,” Williams told Ramos.

“You are the liar. When are you going to give me my apology? You owe me an apology. Say it. Say you’re sorry. … And you stole a point from me. You’re a thief, too!”

Williams continued arguing with tournament officials, fighting back tears, when they came onto the court to hear her pleas for fair treatment.

She insisted male players had called chair umpires much worse and she was being treated differently because she is a woman.

“This is not fair. This has happened to me too many times,” she told tournament referee Brian Earley

“There’s a lot of men who do a lot worse out here. It’s because I’m a woman.”

Serena’s coach Patrick Mouratoglou later admitted he was coaching, but said it’s commonplace. “We have to stop this hypocrisy,” he said. “(Osaka’s coach) Sasha (Bajin) was coaching every point too.”

Mouratoglou didn’t believe, however, that Serena had looked at him, hence why she was adamant no coaching had occurred.

Despite the drama in her first major final, 20-year-old Osaka maintained her focus to serve out the victory.

The presentation ceremony began with booing from the crowd before a tearful Williams said, to wild cheers: “I don’t want to be rude. I don’t want to do questions.

“I just want to tell you guys she played well. Let’s make this the best moment we can and get through it and give credit where credit is due.

“No more booing. Let’s be positive.”

Osaka was also in tears, and said: “I know everyone was cheering for her and I’m sorry it had to end like this. I just want to say thank you for watching the match.

“It was always my dream to play Serena in the US Open finals. I’m really glad I was able to do that.”

With AAP.