Naomi Osaka has defeated Serena Williams in straight sets (6-2, 6-4) to win the 2018 U.S. Open.

The victory is Osaka’s first Grand Slam singles title in her Grand Slam final debut. The 20-year-old also became the first Grand Slam champion from Japan.

Osaka entered Saturday with $3.2 million in career prize money, and will now earn $3.8 million with her US Open victory.