NEW YORK -- After a dramatic US Open final, former world number one Serena Williams said on Saturday that it's not fair that she got three code violations during the match and that she was not happy with the chair umpire.

The 20-year-old Naomi Osaka became the first Japanese to win a Grand Slam singles title in history of the sport as she shocked idol Serena 6-2, 6-4 in the final to win the 2018 US Open.

But the match was marred by Williams' outburst in the second set where she was give three code violations.

Chair umpire Carlos Ramos first warned her for receiving coaching in the second game of the second set, and then handed a point penalty to the American in the sixth game after her breaking a racquet.

Williams continued to argue with Ramos and even yelled at the umpire from Portugal, calling him a "liar" and "thief".

Ramos finally handed Williams a game penalty that put Osaka one game from victory at 5-3 in the second set.

"He alleged that I was cheating and I wasn't cheating. Because I look at my box, it may have looked like I was getting coaching, but I'm not. I'd rather lose than have to cheat to win. I don't need to cheat to win. I've won enough," Williams said in her press conference.

"I'm here fighting for women's rights and for women's equality. For me to say 'thief' and for him to take a game from me, it made me feel like it was a sexist remark. He's never taken a game from a man because they said 'thief'," the 23-time Grand Slam winner added.

"For me it blows my mind. But I'm going to continue to fight for women. I have to go through this and I'm an example for other women players who have emotions, want to express themselves and want to be a strong woman. They are allowed to do that because of today. Maybe it did not work out for me, but it's going to work out for the next person," Williams said.