Tunisia's Ons Jabeur and Tatjana Maria of Germany are currently in the first set of their Wimbledon semi-final on Centre Court.
The winner will become the first player through to
Saturday's showpiece.
2019 winner Simona Halep faces Elena Rybakina in the other last four tie later.
In the men's doubles, Britain's Joe Salisbury and partner
Rajeev Ram are on course to take the first set of their last four match against
Australian duo Matthew Ebden and Max Purcell.