|Wimbledon on the BBC|
|Venue: All England Club Dates: 27 June-10 July|
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Five-time champion Venus Williams reached the Wimbledon semi-finals for the first time since 2009 with victory over Kazakhstan's Yaroslava Shvedova.
Eighth seed Williams - at 36 the oldest Grand Slam semi-finalist for 22 years - beat unseeded Shvedova 7-6 (7-5) 6-3.
An all-Williams final remains possible after top seed Serena beat Russian Anastasia Pavlyuchenkova 6-4 6-4.
In Thursday's semis, Serena will play Russia's Elena Vesnina and Venus will take on Germany's Angelique Kerber.
"We don't really talk too much about it but we are playing doubles later, so we are just happy to be in the semi-finals," Serena told BBC Sport.
Asked about a potential final meeting, she added: "It will be great. Venus is such a tough opponent I want her to win so bad - not in the final if I am there, but if I'm not, I do."
Kerber, the fourth seed, beat Romanian fifth seed Simona Halep 7-5 7-6 (7-2) in the opening match on Centre Court.
Unseeded Russian Vesnina thrashed Slovakian 19th seed Cibulkova 6-2 6-2 in the remaining quarter-final on court one.
John McEnroe, three-time Wimbledon champion: "A lot of people are pulling for Venus to win one more Wimbledon final. She's won this competition five times, and it's often forgotten because of how dominant her sister has been. It's as though she's an after-thought.
"Serena stepped it up when she needed to and served incredibly well. It looks a real possibility Venus could play Serena in the finals of a Grand Slam again."
'I love playing the game'
Venus Williams showed she remains a real threat on the All England Club grass with an impressive win over world number 96 Shvedova.
The champion in 2000, 2001, 2005, 2007 and 2008 made it through to her first Grand Slam semi-final since the 2010 US Open.
At 36, she is the oldest major semi-finalist since Martina Navratilova finished runner-up at Wimbledon in 1994.
"I love playing the game," said Williams, who slipped outside the world's top 100 in 2011 after being diagnosed with the immune system disease Sjogren's Disease. "When you're winning matches it makes it that much sweeter."
The American, who played her first Wimbledon in 1997, recovered from losing an early break to win the opening set tie-break from 5-2 down.
She then dominated the second set, racing into a 5-1 lead and holding off signs of a Shvedova comeback to serve out the win.
"What a tough day on the court," Williams added. "The tie-breaker, it felt like she would win. I felt like my opponent was on fire.
"I felt like the crowd enjoyed all the great points. She got them involved in the last game. We gave them good tennis today."
Top seed Serena finding top form
Serena Williams' presence in the semi-finals is far less of a surprise than that of her sister, but the world number one needed to be at her best to see off Pavlyuchenkova.
The American, 34, converted the only two break points of a desperately tight contest, the first with a crushing backhand return in the opening set, the second thanks to a Pavlyuchenkova double fault in the second.
Williams, the six-time and defending champion, fired down 11 aces and 29 winners as she closes in on a 22nd Grand Slam singles title.
"It was good," she said. "I am excited to be able to win and get through, it felt really good. I knew Venus was up 5-1 and then I saw [the result] on the court [scoreboard], so I was like 'Yay'.
"I am just trying to win my match. I knew I had a tough opponent and one thing I have learnt this year is just to focus on the match."
Vesnina completely dominated against Cibulkova, who appeared to run out of energy after a successful run that began with winning the Eastbourne title ahead of Wimbledon.
The Slovakian can at least take comfort that she does not have to postpone her wedding, which can now go ahead as planned on Saturday.
Seven breaks to six see Kerber through
Australian Open champion Kerber edged past Halep in a contest of terrific rallying, with returns very much dominating over serves.
There were eight successive breaks in the first set, and 13 in total, but the Centre Court crowd was thrilled by much of the shot-making.
Halep was always coming from behind before ultimately succumbing with a double-fault to hand over the first set, and despite twice recovering breaks in the second, a rash of errors gave Kerber a deserved win in the tie-break.
"I think actually it was a good match, on a really high level from both of us," said the German.
"There were a lot of breaks but I think because we are both great return players, it was not so easy to serve actually. It was a really high level match."
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