Melbourne, Australia - Two-time defending champion Victoria Azarenka rolled to another straight-set victory Monday, while third- seeded former world No. 1 Maria Sharapova suffered a surprising upset in the fourth round at the Australian Open.
Azarenka cruised to a 6-3, 6-2 win over American Sloane Stephens on Rod Laver Arena to secure a spot in the quarterfinals with her 18th straight win at Melbourne Park.
Sharapova seemed destined to advance after taking the first set from Dominika Cibulkova, but the 20th-seeded Slovakian roared back to take the final two sets and claim a 3-6, 6-4, 6-1 triumph over the 2008 Aussie Open champ.
The 24-year-old Cibulkova will meet Simona Halep in the quarterfinals after the 11th-seeded Romanian upended eighth-seeded Serbian Jelena Jankovic, 6-4, 2-6, 6-0 on Hisense Arena.
Cibulkova will be making her first ever quarterfinal appearance at Melbourne Park, while Halep became the first Romanian to reach the quarterfinals here since Irina Spirlea in 1997.
Azarenka's quarterfinal opponent will be decided later Monday when fifth- seeded Agnieszka Radwanska squares off with unseeded Spaniard Garbine Muguruza.