Britain's Anne Keothavong lost 6-3 6-2 to American Coco Vandeweghe in the semi-final of the Aegon Trophy.
In the other semi-final Poland's Urszula Radwanska beat Irina Falconi of the US 6-4 2-6 7-5.
Laura Robson and Heather Watson were beaten in the women's doubles final at the Nottingham Tennis Centre.
The British pair went down in straight sets 6-4 6-2 to Greece's Eleni Danilidou and Australia's Casey Dellacqua.
Radwanska went on to beat Vandeweghe in the women's final, 6-1 4-6 6-1.
German Benjamin Becker will meet Dmitry Tursunov of Russia in the men's singles final on Sunday.