Frances Tiafoe celebrated his 21st birthday with the biggest win of his career, knocking off Grigor Dimitrov to reach the quarterfinals in Melbourne.
Author: Sandra Harwitt, Special for USA TODAY Sports
Australian Open: American Danielle Collins upsets No. 2 seed Angelique Kerber
Danielle Collins notched her third upset of a seeded player, pummeling No. 2 Angelique Kerber 6-0 6-2 in the fourth round.