Sofia Kenin, a 21-year-old American, won the Australian Open on Saturday, becoming the youngest U.S. woman to win a Grand Slam since 2002, when tennis icon Serena Williams won.

According to NBC Sports, Kenin beat Garbine Muguruza, a two-time major winner from Spain, in three sets in the Melbourne final. “I knew I needed to come up with the best shot, five best shots of my life,” said Kenin, who hails from Florida. “It got me to win a Grand Slam.”

Previously, Kenin had never gone past the fourth round of a Grand Slam—but said the win would “change” things for her in the future. “I had to play some [of my] best tennis. I did,” Kenin said, according to the Associated Press. “After that, I was on fire. I was ready to take the beautiful trophy.”