Defending champion Serena Williams and Maria Sharapova have advanced to Women's singles quarter-finals of Australian Open Tennis. Today in last-16 matches at Melbourne Park, top seed Williams, crushed Margarita Gasparyan 6-2, 6-1 in 55 minutes. The 34-year-old American is chasing her 22nd Grand Slam title and seventh in Australia.Fifth seed Sharapova, the 2008 champion from Russia, hit 21 aces as she battled to a 7-5 7-5 win over Swiss Belinda Bencic.In Men's Singles, Kei Nishikori has also entered the quarter-finals. The Seventh seed Japanese beat French player Jo-Wilfried Tsonga 6-4, 6-2, 6-4 today.Meanwhile, Indo- Swiss duo of Leander Paes and Martina Hingis has entered the secound round of Mixed Doubles. In opening match, they defeated Russian-British pair of Anastasia Pavlyuchenkova and Dominic Inglot 6-3, 7-5.In Men's Doubles round 3, Indo- Romanian pair of Rohan Bopanna and Florin Mergea lost to the Filipino-Belarusian duo of Treat Huey and Max Mirnyi by 4-6, 3-6.