For the second time in two days, a capacity crowd 80,000 spectators at London Olympic Stadium were treated to a new World record performance as the 4x100m US team of Tianna Madison, Allyson Felix, Bianca Knight and Carmelita Jeter clocked a jaw-dropping 40.82 to improve the previous standard by a huge sixty-five hundredths of a second, the biggest ever improvement on the World record in the history of the event.