England pair Bronte Law and Mel Reid both lost in the last 16 of the Bank of Hope LPGA Matchplay in Las Vegas.
American Danielle Kang survived a late charge from Law, taking the final two holes for a two-man victory.
Reid was beaten 5 & 4 by Minjee Lee of Australia, who started her round with a birdie and went on to dominate.
Sweden’s Anna Nordqvist lost 4 & 3 to Thailand’s Ariya Jutanugarn, but Germany’s Sophia Popov beat Korea’s Inbee Park on the second extra hole.
American Ally Ewing, Korean Eun-hee Ji, Chinese Shanshan Feng and Thai Patty Tavatanakit make up the remainder of the quarterfinals.
Law had tied her match with world number six with a birdie in the 14th, but gave Kang the lead with a bogey in the 17th and the American took the win with a two-putt birdie in the 18th.
“We both played pretty well on the first nine,” Kang said. “She’s definitely outperformed me in the last nine, but I just think I got away with a lot.”