Great Britain's Christine Ohuruogu claimed third at the IAAF Diamond League in Doha as Allyson Felix failed to win her 11th straight race at the meeting.
Felix, who won 200m Olympic gold last year, was edged out by Botswana's Amantle Montsho while two-time Olympic medallist Ohuruogu ran on strongly behind, with all three dipping under 51 seconds.
Olympic bronze medallist and European champion Robbie Grabarz settled for fourth in the men's high jump as Ukraine's Bohdan Bondarenko produced a meeting record 2.33 metres to win.
But there was disappointment for British team-mate Samson Oni, who was taken to hospital with a suspected tendon injury.
Grabarz cleared 2.14m and 2.24m at his first attempts but couldn't get over 2.27m, while Shara Proctor had a best leap of 6.82m to finish sixth in the women's long jump, won by American Brittney Reese.
Tiffany Porter made a solid start to the season, clocking 12.74 seconds to finish fourth in a 100m hurdles race won by American Dawn Harper-Nelson in a world leading 12.60 secs.
Olympic champion and world record holder David Rudisha powered to a confident victory over 800m, with British athletes Michael Rimmer and Andrew Osagie finishing close behind in sixth and eighth.
Elsewhere, Jack Green pulled up on the top bend of the 400m hurdles, which was won classily by Michael Tinsley, and Mark Lewis Francis ranked sixth in the men's 100m B race, in a time of 10.38 secs, while Mukhtar Mohammed came home fifth in the men's 800m B race.
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