Paralympic star Jason Smyth was denied Olympic qualification by an illegal wind reading as he produced his fastest ever 100m in Florida on Saturday.
Smyth's time of 10.17 was .01 inside the London standard but will not be recognised because of the wind reading.
The maximum permissible wind reading is two metres per second but the mark in Clermont on Saturday was 3.6.
The Derry man ran 10.24 at Clermont a fortnight ago before clocking times of 10.34 and 10.35 in Orlando.
Like Oscar Pistorius, the Northern Irish sprinter is aiming to make history later this summer by becoming the first track and field athlete to compete at both the Olympics and Paralympics in the same year.
The 24-year-old was in action on Saturday at the venue which is his regular training base.
The Clermont track is regarded as one of the fastest tracks in the world and Smyth ran his legal personal best of 10.22 at the Florida venue a year ago.
Smyth is scheduled to try again at next Saturday's prestigious Diamond League meeting in New York but his performances this weekend should give him renewed belief that the 10.18 mark is within his compass.