British pair Anne Keothavong and Heather Watson have both been knocked out of the Bank of West Classic in Stanford.
Keothavong's defeat came against Mallory Burdette, who has not won a professional singles match since 2008, with the Brit falling to a 2-6 7-5 6-4 defeat.
Watson, who reached the third round at Wimbledon, fell to a 5-7 6-1 6-4 loss at the hands of world number 37 Yanina Wickmayer.
Both players had hoped to gain some competitive match practice before they represent Team GB at the Olympics.
