Casey Phair on Tuesday became the youngest player to feature at a Women's World Cup after coming on as a substitute for South Korea against Colombia aged 16 years and 26 days.
The striker was born in the United States and was called up by the country at youth level, but has now made her debut for South Korea.
She came on in the 78th minute in Sydney and so trumped Nigeria's Ifeanyi Chiejine, who was 16 years and 34 days when she played at the 1999 World Cup.
Phair, born to an American father and Korean mother, is the first player of mixed descent to make the senior South Korean women's football squad.
Speaking on the eve of the Colombia game, South Korea's English coach Colin Bell said he was eager to protect the teenager.
"So now she's in the squad, then we just take it day by day, so I don't really want to hype up a young player too much before she's even played," he said.
"That's why I've been safeguarding her from the media."