Marlon Devonish could see his 100m personal best at the Oslo Golden League meeting removed from the records because of an administrative mistake.
Devonish finished third in the A final as an injury replacement
"I didn't know what the rules were - you would think they would sort that out beforehand," Devonish said.
Devonish ran 10.20 secs in the B final then filled in for the injured Michael Frater and ran 10.08 in the A final.
But, as the times of the two races are combined, an IAAF rule prevents anyone running the same event twice.
Golden League rules mean a runner in the B final who records a faster time than one in the A final will be placed ahead of that runner in the overall results.
Devonish, 31, finished an outstanding third in his second final of the night, behind world record-holder Asafa Powell and European champion Francis Obikwelu.
He only found out an hour afterwards that he had been disqualified and is still hoping to have the decision overturned.
"I was doing them a favour. They asked me when I was ready to go out on the track to do the B race," he told BBC Five Live.
"Obviously I ran very well - a PB, which I've very pleased with - but I'm a bit gutted with the way it turned out."
Devonish kept his prize money as his winning time in the earlier race was still the third quickest of the two races.