Johanna Konta and Heather Watson crash out in Birmingham

Rain meant the previous day's play had to be concluded on Friday before the scheduled quarter-finals could get under way but there would be no home interest in the last eight as Konta and Watson joined Petra Kvitova and Agnieszka Radwanska as big-name early casualties at the event.

British number one Konta has struggled for form recently and looked off the pace as Belgium's Yanina Wickmayer eased to a 6-3 6-3 win.

Watson's struggles also continued as she too was beaten in straight sets, 7-5 6-4 by Barbora Strycova.

When the quarter-finals did get going, Angelique Kerber saw the defence of her title come to an end with defeat to Carla Suarez Navarro.

The German second seed fought back from losing the opening set and was three times within two points of victory in the deciding set but was beaten 6-4 1-6 7-5 by the world number 16 from Spain.

In the semi-finals Navarro will play Madison Keys after she also battled back from a set down to beat Latvia's rising star Jelena Ostapenko 6-7 6-4 6-2 with a win that means the American, seeded seven in Birmingham, can achieve a top-10 world ranking if she wins her last-four clash on Saturday.

The other semi-final will be between Coco Vandeweghe, who won the Ricoh Open in 's-Hertogenbosch last week, and Barbora Strycova.

Vandeweghe continued her fine grass-court form with a 6-4 6-2 win over Konta's conqueror Wickmayer, while Strycova was also a straight sets winner against French Open quarter-finalist Tsvetana Pironkova 6-2 7-5.