Serena Williams beat sister Venus in the women's singles fourth round at Wimbledon, while the younger Williams sister's rivals Maria Sharapova and Victoria Azarenka also advanced to the quarter-finals on Monday.
In the 26th career meeting between the siblings, Serena dominated with her steady serve and big hitting from the back of the court to win 6-4, 6-3 on Centre Court, extending her Grand Slam winning streak to 25 matches.
The win sent the top-ranked Williams one step closer in her quest for a fourth straight Grand Slam title, a feat last accomplished by the younger Williams in 2003. If Serena can triumph again, only the US Open would stand in her way of becoming the first player to complete a calendar-year Grand Slam - a sweep of all four majors in the same season - since Steffi Graf in 1988.
When Venus hit a backhand long on break point to end the match, Serena showed no emotion and did not celebrate. She walked slowly to the net, where the two sisters hugged. They walked off the court together.
"It's hard to feel excited about (beating) someone you root for all the time no matter what and who you love so much and she's your best friend in the world," Serena said. "It's never easy but you just play for the competition and enjoy the moment."
Both sisters have won Wimbledon five times, but Serena also has a total of 20 Grand Slam titles. Another Wimbledon title will put her just one behind Graf, who holds the Open era record with 22.
"It was really good for me to get it done in straight sets, and just put this behind me and just move forward," Serena said.
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.
Russia's Maria Sharapova celebrates beating Kazakhstan's Zarina Diyas in their women's singles fourth-round match of the 2015 Wimbledon Championships at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. Sharapova won 6-4. 6-4. (AFP Photo)
Sharapova overcomes Diyas
Sharapova came through a spirited test from Zarina Diyas, eventually subduing the tenacious scrambler from Kazakhstan 6-4 6-4 after a brief scare in the second set.
The Russian, who had not been past the fourth round since 2011 at the tournament she won for the only time as a teenager 11 years ago, will now face American Coco Vandeweghe in the last eight.
Her victory over Diyas was far from comprehensive, but it was further evidence nonetheless that things are looking good for the fourth seed as she maintained her unblemished record of not dropping a set up so far.
She found her range early under hazy skies on Court One, peppering the baseline with her usual array of missiles and breaking for a 3-1 lead with a rasping crosscourt winner. Diyas, who surged 129 places up the rankings in 2014 to 34th, showed she was no soft touch by breaking back in the ninth game, having saved two set points, but Sharapova's extra power told and she clinched the first set on her opponent's serve.
There was a clear shift in momentum, however, at the start of the second as Sharapova's concentration slipped and the Kazakh broke and held for a 3-1 lead. Ultimately, however, Diyas lacked the weapons to maintain that advantage and the five-times grand slam champion broke back for 3-3 and then closed out the match on the Diyas serve when the Kazakh sent a backhand long.
Victoria Azarenka of Belarus reacts after winning a point during her women's singles third-round match of the 2015 Wimbledon Championships against Belinda Bencic of Switzerland at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. (Reuters Photo)
Azarenka sets up Serena clash
23rd-seed Azarenka, a two-time Wimbledon semi-finalist from Belarus, beat upcoming teenager Belinda Bencic of Switzerland 6-2, 6-3, to set up a quarter-final clash against Serena Williams. Two-time Australian Open champion Azarenka has never reached the final at The All England Club.
Coco Vandeweghe of the USA celebrates after winning her women's singles third-round match of the 2015 Wimbledon Championships against Lucie Safarova of the Czech Republic at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. Vandeweghe won 7-6 (1), 7-6 (4). (Reuters Photo)
CoCo and Madison join Serena
CoCo Vandeweghe and Madison Keys joined Serena to mark the first time three American women reached the women's singles quarter-finals at Wimbledon 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.
"I'm not really considering it like, 'Wow, a breakthrough,'" she said. "I had set goals of what I wanted to do, and because I'm achieving it doesn't mean it's a breakthrough."
Vandeweghe will next face fourth-seeded Sharapova, the 2004 champion.
Madison Keys of the United States celebrates winning her women's singles third-round match of the 2015 Wimbledon Championships against Olga Govortsova of Belarus at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. Keys won 3-6, 6-4, 6-1. (AP Photo)
The 20-year-old Keys got to the Wimbledon quarterfinals for the first time, beating 122nd-ranked Olga Govortsova of Belarus 3-6, 6-4, 6-1. Keys, who reached the semi-finals at the Australian Open this year, has now beaten three players here who were ranked outside the top 100.
"I definitely feel like when I'm walking out onto the courts, not only do I feel people are expecting me to win but I am expecting me to win," Keys said.
In other results, 13th-seeded Agnieszka Radwanska of Poland beat 28th-seeded Jelena Jankovic of Serbia 7-5, 6-4. Radwanska was the runner-up in 2012.
Garbine Muguruza, the 20th seed from Spain, upset 5th-seeded Caroline Wozniacki of Denmark 6-4, 6-4, while French Open semi-finalist Timea Bacsinszky, seeded 15th, beat unseeded Monica Niculescu of Romania 1-6, 7-5, 6-2.
(With inputs from AP and Reuters)