Dwain Chambers has run his first competitive 100 metres race since he was cleared to compete at this summer's London Olympics.
The 34-year-old finished a disappointing sixth at the Ponce Grand Prix in Puerto Rico on Saturday.
Trinidad & Tobago's Keston Bledman claimed victory in 10.12 seconds, with Jamaica's Nickel Ashmeade second in 10.15s and American Trell Kimmons third in 10.18s.
British Chambers, who was also beaten by compatriot Tyrone Edgar (10.42s), finished well back in 10.52s.
Although he was prevented from participating at the Beijing Games, Chambers is eligible for selection for London after the British Olympic Association's lifetime ban for drugs cheats was ruled non-compliant by the Court of Arbitration for Sport last month.
