In heat 1 of the semifinal round, Derek Redmond tore his hamstring 250 meters to the finish line and was disqualified due to outside assistance from his father Jim.

Despite the results, the crowd gave him a standing ovation, and became as one of the well-remembered moments in Olympic's history.

In heat 2 of the semifinal round, Quincy Watts ran the number 2 time in history, 43.71, only surpassed by the world record held by Butch Reynolds.

At those trials, Danny Everett had run the previous number time in history 43.81, while Reynolds did not qualify.

In the final, Watts again improved the number 2 time in history while breaking the Olympic Record with his 43.50 win.

[2] Angola, the Central African Republic, Costa Rica, Grenada, Lesotho, Mauritania, and Qatar appeared in this event for the first time.