Osaka, 20, beat Williams 6-2 6-4 in Saturday's final, but the crowd booed as she received the trophy.

Williams got a code violation for coaching, a penalty point for racquet abuse and a game penalty for calling the umpire a "thief" in New York.

"At the time I did think they were booing at me," said Japan's Osaka.

Speaking on The Ellen DeGeneres' Show she said: "I couldn't tell what was going on, it was so loud and a little bit stressful."

Osaka remained composed throughout Williams' repeated on-court protests at umpire Carlos Ramos, as she ended the 36-year-old's bid for a record-equalling 24th Grand Slam title.

"When you are little, you are taught not lo look when the opponent gets angry, you are told to turnaround and try and focus," said Osaka. "In my mind I really wanted to know what was going on. I heard a lot of people in the crowd making noises and I really wanted to turn around."

Osaka became overwhelmed by emotion during the trophy presentation as boos - seemingly aimed at the umpire's decision to penalise Williams - rang around the court.

Discussing what Williams had whispered to her, during the presentation, she said: "She said was proud of me and to know the crowd weren't booing at me."

Osaka - who was born in Japan and raised in the United States - has climbed to a career-best seventh in the world rankings after winning her first Grand Slam title.

"For me, I don't feel sad because I wouldn't even know what I'm expected to feel," added Osaka.

"I don't think I even thought about feeling sad because there's no experience for me to draw on [from] any other Grand Slam final."