Keys reaches Osaka quarters

Osaka, Japan ( - American Madison Keys made quick work of her second-round opponent Thursday and advanced to the quarterfinals at the Japan Women's Open.

The 18-year-old Keys, seeded sixth, needed just 51 minutes to close out an easy 6-4, 6-0 win over China's Zhang Shuai on the hardcourts at Utsubo Tennis Center.

Next up for Keys is another Chinese player, Zheng Jie, who ousted ninth- seeded Kristina Mladenovic of France, 6-7 (5-7), 6-2, 6-0, in a 2-hour, 20- minute affair.

Japan's Misaki Doi also moved on with a 7-6 (7-3), 6-4 win over 43-year-old countrymate and 2010 Osaka runner-up Kimiko Date-Krumm, setting up a Friday quarterfinal against third-seeded Samantha Stosur, the 2009 Osaka champ and 2011 runner-up.

Friday's other quarterfinals will feature fifth-seeded Canadian Eugenie Bouchard against Czech qualifier Barbora Zahlavova Strycova and Japanese wild card Kurumi Nara against Slovenia's Polona Hercog.