Serena Williams remains on course after sweeping into third round of Australian Open

• American breezes through second set against Nina Stojanovi
• Hsieh Su-wei upsets eighth seed Bianca Andreescu in Melbourne

Serena Williams overcame a spirited Nina Stojanovi 6-3, 6-0 on a sun-drenched Rod Laver Arena to reach the third round of the Australian Open for the 19th time.

The American, again sporting her distinctive one-legged catsuit, needed to find her best game at times in the first set against a Serbian 15 years her junior who was playing in her fourth grand slam.