Los Angeles - Play at the WTA Tour's Volvo Car Open clay court tournament was postponed on Saturday after heavy rains swept through the Charleston area.
Both the semi-finals and the finals will be played on Sunday with American seventh seed Madison Keys and Kiki Bertens of the Netherlands taking the court first.
Bertens is the only player to have reached the semis without dropping a set.
That will be followed by German fifth seed Julia Goerges battling Anastasija Sevastova for a place in the afternoon final.
Eighth seed Sevastova is seeking to become the first Latvian to win the singles title here while Goerges is aiming for her second title of 2018 after winning previously in Auckland.
There is one doubles match scheduled to take place on Sunday between the end of the semis and the start of the singles final.