Webb won the British Open at Turnberry in 2002. Another former champion, 2008 winner Jiyai Shin of South Korea, had the first sub-par round at Royal Liverpool, followed by 16-year-old England amateur Charley Hull, Japan's Ai Miyazato and Welsh pro Lydia Hall.
Taiwan's Yani Tseng, bidding for her third successive British Open, was a stroke behind with less than a third of the field in the clubhouse. Joining her were 15-year-old New Zealand amateur Lydia Ko, Sweden's Carin Koch, Japan's Yuki Ichinose and Koreans Inbee Park and Chella Choi.
Paula Creamer and Natalie Gulbis were the leading Americans with 73s.