Naomi Osaka defeated her hero Serena Williams, 6-2. 6-4, to win the U.S. Open on Saturday, the first major title of the 20-year-old’s career.

Williams, attempting to tie the record with her 24th Grand Slam title, was levied a game penalty in the second set in what turned into a shocking series of events.

Chair umpire Carlos Ramos assessed Williams a coaching violation after her longtime coach, Patrick Mouratoglou, motioned from the player’s box that Williams should go to the net more often. Williams, 36, disputed the violation and then told Ramos that she is not a cheater.

Williams spoke with Ramos again, demanding an apology for “stealing” a point from her.

“You owe me an apology,” Williams said. “I have never cheated in my life.”

She called Ramos a thief, and he assessed her a third code violation for verbal abuse, resulting in a game penalty that put Osaka up 5-3 and one game from the championship.

Williams said she was being treated differently from male players who, she argued, get away with much harsher language and behavior on court.

Osaka won the match quickly after that, a bittersweet ending to a battle she had been fighting admirably against her idol.

Williams was attempting to win her 24th Grand Slam title to tie the record set 45 years ago to the day by Margaret Court at the U.S. Open. In another bit of coincidence, Sept. 8 was also the day Althea Gibson became the first black player to win the singles title at the tournament’s predecessor, the U.S. Championships, in 1957.

Williams, 36, was also trying to break Chris Evert’s record of six U.S. Open singles titles.

Osaka, 20, was making her debut in a Grand Slam final. Not since 18-year-old Monica Seles defeated 35-year-old Martina Navratilova in the 1991 U.S. Open final has there been such an age gap between finalists.

Osaka, who is of Haitian-Japanese ancestry and was raised in the United States but plays for Japan, had before never made it past the fourth round of a Grand Slam. She was the youngest woman to reach the final at Flushing Meadows since Caroline Wozniacki did it as a 19-year-old in 2009.

The post-match ceremony was the most uncomfortable in memory at the U.S. Open. Williams held her face in a forced, closed-lipped smile as tears ran down Osaka’s cheeks while U.S. Tennis Association President Katrina Adams spoke.

“Naomi, welcome to the big stage. Serena, welcome back,” Adams said as the crowd booed loudly.

“Perhaps it’s not the finish that we were looking for today but Serena, you are the champion of all champions. This mama is a role model, and respected by all.”

Williams hugged Osaka and tried to comfort her during the speeches. ESPN’s Tom Rinaldi was left to the post-match interviews and Williams respectfully declined to answer.

“I don’t want to be rude, I don’t want to do questions, but this was her first Grand Slam,” Williams said through tears. “Um, I know you guys were here rooting and I was rooting, too, but let’s make this the best moment we can, we’ll get through it . . . Let’s not boo anymore. Let’s get through this.

Osaka gave a brief nod as the crowd cheered for her for the first time all night. Her voice was shaky when she thanked her mother and the crowd.

“I know that 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,” Osaka said. “It was always my dream to play Serena in the U.S. Open finals so I’m really glad I was able to do that. Thank you.”

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