Serena Williams beats sister Venus to reach last eight

Serena Williams of the U.S.A. embraces Venus Williams of the U.S.A. after winning their match at the Wimbledon Tennis Championships in London, July 6, 2015.[Photo/Agencies]

Monday's victory improved her career record against Venus to 15-11, including 8-5 in Grand Slams and 4-2 at Wimbledon. This was the sisters' first meeting at a major since the 2009 Wimbledon final, which was won by Serena.

Serena broke twice in each set and lost serve just once. She had 10 aces, as well as 36 winners and 13 unforced errors.

Venus Williams, playing in her 18th Wimbledon, was the oldest woman in the draw at 35.

This was the earliest all-Williams match in a Slam since they met in the fourth round at the 2005 U.S. Open. Venus was asked whether it felt different playing her sister at such an early stage.

"It's definitely anticlimactic if this isn't a semifinal or a final," she said. "It's different. Especially when she's going for something this historic, which is achievable for her."

Serena will next face another familiar opponent _ Victoria Azarenka, the two-time Australian Open champion from Belarus. Azarenka beat 18-year-old Belinda Bencic of Switzerland 6-2, 6-3.

Williams holds a 16-3 career advantage against Azarenka, including a 9-0 record in Grand Slam matches.

Serena was one of three American women to reach the Wimbledon quarterfinals Monday, along with CoCo Vandeweghe and Madison Keys. It's the first time that's happened since 2004 when Jennifer Capriati, Lindsay Davenport and Serena made it to the final eight.

The 47th-ranked Vandeweghe surprised French Open runner-up and sixth-seeded Lucie Safavora 7-6 (1), 7-6 (4). Vandeweghe had never gone past the third round of any major until this year's Wimbledon.