Elaine Thompson won a 100m at her first meet since sweeping the Olympic sprints, but she actually raced about 200 meters in Lausanne, Switzerland, on Thursday.
Thompson, who won the 100m and 200m in her Olympic debut in Rio, was one of seven runners in an eight-woman 100m field in Lausanne who did not react to a second gun indicating a false start.
So Thompson and others had to trudge back from the finish line to the start in order to re-run the race.
About nine minutes after the false start, Thompson won the 100m in 10.