The US quarter of Tianna Madison, Allyson Felix, Bianca Knight and Carmelita Jeter shattered the previous record of 41.37, which had been set by the German Democratic Republic in 1985, to establish a new time of 40.82, over half a second faster.

It is the second World record to be established on the track in these Olympic Games and comes a day after David Rudisha broke the 800 meter record on Thursday.

Jamaica finished second, while Ukraine won a very creditable Bronze medal.

The race had always been expected to be fast with America fielding a team led out by 100 meters gold medalist Shelly Ann Fraser-Pryce and including, Sherone Simpson, Veronica Campbell Brown and Kerron Stewart.

Fraser-Pryce may have been Olympic 100 meters champion, but she was always training Madison, who flew out of the blocks and handed over a lead to Felix. The new 200 meter gold medalist is having a fantastic Games and widened the lead. Knight held the gap and Jeter tore down the final straight raising the baton in triumph as she crossed the line.

The DDR's record had lasted for 27 years and given what is now known about the training 'methods' of former East German athletes to break it is an incredible achievement, to break it by over half a second is just incredible.