MELBOURNE, Australia (AP) Naomi Osaka, an 18-year-old tennis player from Japan, faced a room overflowing with Japanese journalists on Tuesday after beating Donna Vekic in the first round of the Australian Open for her first-ever win at a Grand Slam tournament.

As is customary at news conferences at Melbourne Park, the moderator called for questions in English first. Osaka looked alarmed, then asked sheepishly, ''English only?''

She was serious - she is still learning Japanese.

Osaka was born in Osaka, Japan's second city, to a Haitian father and Japanese mother. Her family moved to the United States when she was young and she now trains predominantly in Florida with her father, though she also spends some time in Japan with coaches from the Japanese Tennis Association.

Even though she's not completely fluent in the language, she's now representing Japan professionally and is one of the country's most highly touted rising stars.

Speaking like a typical teenager - few words, lots of ''likes'' - she said the decision was a good one for her.

''I just like the food and stuff,'' she said. ''And I'm really introverted so I feel that I fit in more there.''

Osaka made her breakthrough on the WTA Tour two years ago when she qualified as a 406th-ranked 16 year old for the Bank of the West Classic in Stanford, California, and beat former U.S. Open champion Samantha Stosur in the first round.

Now ranked No. 127, Osaka won three matches to qualify for the main draw at Melbourne Park before beating Vekic 6-3, 6-2 on Tuesday. Her next opponent is 18th-seeded Elina Svitolina of Ukraine.

She credits her improved consistency on the court with a newfound maturity and the fact she's no longer limited in how many tournaments she can play by the WTA's age restrictions.

''This whole time I was just waiting to turn 18,'' she said. ''So maybe my mind was like `You're 18 now, you can play a lot of matches' and not stress out too much about playing a few tournaments.''

Her goal this year is to crack the top 100 and win a tournament. Off the court? She wants to master Japanese.

''I get really nervous when I hear, like it's really fast, you know. Sometimes it sounds like they're rapping so then I'm just like, `Oh my God, I didn't hear the first part of the question.' Then I look like an idiot and I don't want to look like an idiot.''

When asked what makes her more nervous, addressing a group of Japanese reporters or playing in front of 10,000 people at a Grand Slam, the room erupts in laughter.

''That's such a mean question!'' she protests. Then, after a pause, she adds, ''No comment.''