With composure that belied her age, Coco Gauff claimed the biggest win of her young career on Friday with a stunning upset of defending champion Naomi Osaka at the Australian Open to reach the fourth round. The 15-year-old American took advantage of a misfiring Osaka for a brutally efficient 6-3 6-4 win in just 67 minutes on Rod Laver Arena.
Gauff, who had beaten seven-times Grand Slam champion, Venus Williams, in her Australian Open debut on Monday, said the win over Osaka ranked “somewhere around the top” of her biggest scalps.