Naomi Osaka working to be more mature

US Open winner Naomi Osaka admitted that she was naturally shy and said one of her key goals in the off-season had been to work on her confidence and become more mature.

The likable 21-year-old Japanese was catapulted into the global spotlight when she won the US Open last year, beating Serena Williams, whose tantrum at the umpire in the final almost overshadowed her achievement.

The breakthrough made her a new standard bearer for tennis in her homeland, Asia and the next generation of women, and she is working hard on living up to the hype.

While focusing on her game during the off-season, she has also been concentrating on better dealing with the off-court responsibilities that come with being a major winner.

"For me one of my biggest goals is to be more mature, like to mature as a person," she said ahead of her opening round clash at the Australian Open against Poland's Magda Linette next week.

"And I feel like in a way I am, but in other parts I'm very, like, three years old mentality, you know? I feel like just levelling that out is one of my biggest goals I had during the off-season."