LONDON, July 6 (Xinhua) -- Five-time champion Serena Williams and 2004 winner Maria Sharapova reached the quarterfinals of the Wimbledon Championships here on Monday.
Serena beat her elder sister Venus 6-4, 6-3 in a Grand Slam match for the first time in six years , while fourth seed Maria Sharapova defeated Zarina Diyas of Kazakhstan 6-4, 6-4.
Serena, two years younger than her sister, thus improved her record with Venus to 15 wins and 11 losses.
Sharapova, who has yet to drop a set at this year's tournament, will next play unseeded Coco Vandeweghe, who upset sixth seed Czech Lucie Safarova 7-6, 7-6 to reach a Grand Slam last eight for the first time.
Another American Madison Keys also booked a berth in the quarterfinals with a 3-6, 6-4, 6-1 win over Olga Govortsova of Belarus.