Serena Williams squandered four match points and blew a 5-1 lead in the decider as seventh seed Karolina Pliskova produced a stunning fightback to claim a 6-4 4-6 7-5 quarter-final victory over the American at the Australian Open.
US Open champion Naomi Osaka has beaten Elina Svitolina to reach her first Australian Open semi-final.
Rafael Nadal kept the flag flying for the old guard at the Australian Open with a 6-3 6-4 6-2 win over American Frances Tiafoe.
Greek sensation Stefanos Tsitsipas has added another chapter to his Australian Open odyssey by claiming a maiden Grand Slam semifinal for the Mediterranean nation.
An exhausted Kei Nishikori battled from two sets down to outlast Spain's Pablo Carreno Busta 6-7(8) 4-6 7-6(4) 6-4 7-6(8) in an epic encounter.
If having his Australian Open title defence ended early was not painful enough for Roger Federer, there was the additional sting of being beaten by a tyro with plenty of similarities to his younger, fearless self.
World number one Simona Halep set up a mouth-watering encounter with Serena Williams by beating the American's older sister Venus in the third round of the Australian Open yesterday.
Roger Federer weathered a stern test from Britain's Dan Evans to reach the Australian Open third round.
Germany's Julia Goerges became the first seeded player knocked out of the Australian Open when American Danielle Collins came from a set down to record a 2-6 7-6(5) 6-4 victory in the first match on Margaret Court Arena.
Former Queenstown player Ben McLachlan and his German doubles partner have beaten Kiwi Michael Venus and Raven Klaasen in the final of the ASB Classic in Auckland.