Barbara Parker ran a new British record of 9:24.24 to finish fourth in the 3,000m steeplechase at the Prefontaine Classic in Eugene.
Parker eclipsed Helen Clitheroe's four-year-old mark of 9:29.14, set at the Beijing Olympics, as Kenya's Milcah Chemos took victory in a world-leading 9:13.69.
Shara Proctor won the long jump with a leap of 6.84m, a new outdoor personal best. Proctor, the world indoor bronze medallist, moved up to fifth in the world rankings this season.
But things went less well for Phillips Idowu in the triple jump after he withdrew from the competition after three jumps. The world silver medallist, who has had a decent start to the year, pulled out after fouling his third attempt.
He had to settle for third with a best of 17.05m, with world champion Christian Taylor sending out a pre-Games warning by winning with a world-leading 17.62m. Fellow American Will Claye was second in 17.48m.
Liu Xiang established himself as the firm favourite for Olympic gold in the 110m hurdles with a stunning 12.87 run. A following wind of 2.4m/s, beyond the legal limit, meant the time could not count for record purposes, but he was too good for a strong field which included world champion Jason Richardson and former world number one David Oliver.
Britain's world bronze medallist Andy Turner was last in 13.46, still inside the Olympic A standard.
There was disappointment for Holly Bleasdale in the pole vault as she could only manage to clear 4.28m to finish seventh.
American Sanya Richards-Ross showed Christine Ohuruogu just how tough a task she faces to retain her Olympic 400m crown by running a world-leading 49.39.
Justin Gatlin continued his impressive start to the season by winning the 100m in 9.90, his third sub-10 clocking of the year, while Allyson Felix won the 200m in 22.23.