Jennifer Brady made a recovery from a set down against two-time Grand Slam winner Garbine Muguruza.
Garbine Muguruza had to struggle two days after ending the current comeback of Kim Clijsters as Spain's double grand Slam champion grappled with her world number 39 opponent.
Kim Clijsters lost her first match in her second tennis comeback on Monday following a 6-2, 7-6 (8/6) defeat to Garbine Muguruza.
Garbine Muguruza gave up a one-set lead and lost the Australian Open final to fiery American 14th seed Sofia Kenin.
Sofia Kenin defeated Garbine Muguruza 4-6, 6-2, 6-2 in the Australian Open final to win maiden Grand Slam title on Saturday.
Few would have predicted that either Sofia Kenin or Garbine Muguruza would reach the Australian Open final but they have fought their way through to stand one win from glory.
Sofia Kenin stunned world number one and home hope Ashleigh Barty to reach her first Grand Slam final at the Australian Open.
Garbine Muguruza defeated Anastasia Pavlyuchenkova 7-5, 6-3 in a hot and sunny Melbourne to reach the Australian Open semi-finals for the first time.
Nick Kyrgios beat Russia's Karen Khachanov 6-2, 7-6 (7/5), 6-7 (6/8), 6-7 (7/9), 7-6 (10/8) in the third round of the Australian Open.
Elina Svitolina became the latest seed in the women's draw to make an exit after being well beaten by unseeded Garbine Muguruza in the third round.
China Open: Garbine Muguruza lost in a match which did not start until nearly 1:00am and concluded at 2:31am on Sunday in Beijing.
Novak Djokovic defeated Jo-Wilfried Tsonga 6-3, 7-5, 6-4 in straight sets.
Garbine Muguruza breezed past her opponent but insisted the clash had not been plain sailing.
Muguruza, who is currently ranked 15th, feels tennis suffers less from sexism than other sports.
Novak Djokovic called for the doctor during the second set against Adrian Mannarino but put aside his discomfort to progress 4-6, 6-2, 6-1.
Muguruza's defeat leaves just top seed Simona Halep, number seven Karolina Pliskova and 10th seed Madison Keys as the remaining top-ranked contenders after two rounds.
Serena, 36, missed Wimbledon last year while preparing to give birth and has endured a rocky time since resuming her career earlier this year.
Simona Halep reached her third French Open final where she will face US Open winner Sloane Stephens for the title.
