Australian Open champion Angelique Kerber stands between Serena and Venus Williams from clashing in the Wimbledon final for an incredible fifth time.
The ageless superstars moved to within a win each of penning one of the sporting stories of the year with a pair of straight-set quarter-final triumphs on Tuesday.
Top-ranked Serena stepped up her title defence with a steely eyed 6-4 6-4 win over Anastasia Pavlyuchenkova after Venus advanced to the last four at the All England Club for the first time in seven years with a 7-6 (7-5) 6-2 defeat of Yaroslava Shvedova.
"We're just happy to be in the semi-finals. It's so cool, it's just great," Serena beamed after booking a date on Thursday with another Russian in unseeded Elena Vesnina, who ousted Dominika Cibulkova 6-2 6-2 to make her first major semi-final at 29.
But continuing her extraordinary tennis renaissance, 36-year-old Venus is the oldest player to reach the Wimbledon last four since Martina Navratilova in 1994.
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It's been 16 years since the veteran landed her first of five crowns on London's hallowed grass courts, and five years after being diagnosed with career-threatening Sjogren's syndrome.
"Semi-finals feels good," Venus said.
"But it doesn't feel foreign at all, let's put it that way.
"I love playing the game. I always have of course and when you're winning matches it makes it that much sweeter.
"The wins and the losses, they all lead to these big moments. You can't always have these big moments. If you're Serena Williams, I guess that happens a lot, but as Venus Williams this is an awesome day."
Champion in 2000, 2001, 2005, 2007 and 2008, eighth-seeded Venus will be contesting her 20th grand slam semi-final - but first in six years - as she continues her pursuit of an improbable eighth major singles title.
The former world No.1 has won all eight previous semi-finals at Wimbledon, including the 2000 decider when she defeated 18-year-old Serena en route to her first title at SW19.
Despite her impeccable credentials, Venus will be up against an inspired opponent.
After taking 30 slams to make her breakthrough in Melbourne, Kerber is now eyeing a second in six months after denying Romanian fifth seed Simona Halep 7-5 7-6 (7-2) in a rollercoaster quarter-final that featured 13 breaks in 24 service games.
"I won the last point and that's what counts," Kerber said.
At 29, Kerber - a semi-finalist in 2012 too - believes she's at the peak of her powers.
She is the only woman not to have dropped a set yet in five matches this campaign and rates her chances of toppling Venus as at least 50-50.
"I've had a great year so far with the Australian Open title and I'm feeling so good," Kerber said.
Serena is four from four against Vesnina and another victory over the world No.50 would propel the American to within one win of a seventh Wimbledon crown - and record-equalling 22nd grand slam title to match Steffi Graf's open-era benchmark.
