Coco Gauff, at age 19, won her first major championship by defeating Aryna Sabalenka in the U.S. Open final. Gauff thanked those who doubted her, saying their skepticism fueled her determination to succeed. She is the first American teenager to win the tournament since Serena Williams in 1999. Gauff's victory marks a "Welcome to the big time!" moment for the young tennis player, who burst onto the scene at 15 by becoming the youngest qualifier in Wimbledon history.