Naomi Osaka of Japan on Saturday beat Czech Petra Kvitova in the Australian Open final to win back-to-back Grand Slam titles.
It comes four months after the 21-year-old defeated Serena Williams in the US Open final.
From number 72 a year ago, Osaka is the new world number one following her 7-6 (7-2) 5-7 6-4 win over Kvitova.
She went into the final in Melbourne as the fourth seed.
Eighth seed Kvitova, 28, was bidding for her first major title since being stabbed in a knife attack.
Osaka was all smiles during the trophy presentation – in contrast to her US Open victory – and she continued a tradition of slightly awkward acceptance speeches.
“Erm, hello. Sorry, public speaking isn’t my strong point so I hope I can get through this,” she said.
“I read notes before this but I still forgot what I was meant to say. Thank you everyone, I am really honoured to have played in this final.”
