World number two Aryna Sabalenka is through to the Australian Open third round but third seed Garbine Muguruza suffered an early exit in Melbourne.
Belarusian Sabalenka, 23, had to come from behind to defeat China’s Xinyu Wang 1-6 6-4 6-2.
Spain’s two-time Grand Slam winner Muguruza fell in straight sets to France’s Alize Cornet, losing 6-3 6-3.
Elsewhere, Polish seventh seed Iga Swiatek safely progressed while sixth seed Anett Kontaveit was knocked out.
Swiatek, 20, reached round three with a 6-2 6-2 victory against Sweden’s Rebecca Peterson.
However Estonia’s Kontaveit lost 6-2 6-4 to Denmark 19-year-old Clara Tauson, who claimed her first win over a top-10 opponent.
Russian 10th seed Anastasia Pavlyuchenkova won 6-2 6-2 against Samantha Stosur as the Australian 37-year-old’s singles career came to an end.
Belgian’s Elise Mertens, the 19th seed, beat Romania’s Irina-Camelia Begu 6-3 6-2, Russian 25th seed Daria Kasatkina won 6-2 6-3 against Poland’s Magda Linette, while Slovenia’s Tamara Zidansek overcame Britain’s Heather Watson 7-6 (7-4) 6-4.