The US Open has fined Serena Williams $17,000 for three code violations during her loss in Saturday's women's singles final, the United States Tennis Association said.

Saturday's match between Williams and Naomi Osaka in New York's Arthur Ashe Stadium was marred by controversy in the second set after umpire Carlos Ramos penalized Williams a point and then an entire game. Osaka beat Williams in straight sets -- 6-2, 6-4 -- to win her first Grand Slam title.

Ramos first issued a warning to Williams after ruling that her coach, Patrick Mouratoglou, gave her hand signals that Ramos said constituted illegal coaching. Williams denied the accusation and could be heard repeatedly demanding an apology from Ramos.

"Williams approached the net and told the umpire, "I don't cheat. I'd rather lose. Every time I play here, I have problems."

The 23-time Grand Slam champ didn't elaborate on the previous incidents, but in 2009 she was docked a point after she was deemed verbally abusive to a lineswoman. In 2011, Williams' opponent Sam Stosur was awarded a key point, and thus the game, when an umpire ruled Williams yelling, "Come on," had hindered Stosur before she made contact with the ball.

Later in Saturday's match, Ramos docked Williams a point after she smashed her racket upon misplaying a shot. Ramos then issued Williams a full game penalty after she called him a "thief," saying the comment amounted to verbal abuse.

"You stole a point from me, and you are a thief," Williams told him.

It was a case she also was heard making to tournament referee Brian Earley and supervisor Donna Kelso, who Williams summoned to the court after Ramos penalized her.

"There are men out here that do a lot worse, but because I'm a woman, you're going to take this away from me?" Williams said.

"That is not right."

At a post-match news conference, she accused Ramos of sexism and also voiced displeasure with an incident last week in which chair umpire Christian Rask handed Alize Cornet a code violation for taking off her shirt, which she had on backwards, during a match. (CNN)