The USA quartet of Michael Phelps (1:43.31), Ryan Lochte, Ricky Berens and Peter Vanderkaay took gold in the 4x200m freestyle in a world record of 6:58.56. The standard had stood to the USA at 7:03.24 since the world championships in March 2007. The pace of progress is breathtaking.
Victory gave Phelps his fifth fold medal of the Games and 11th of his career, an Olympic record in itself.
The Russian quartet took silver on 7:03.70 and Australia bronze on 7:04.98. As a measure of the tightness of the race, Britain finished 6th on 7:05.92. Six teams inside 7:06.
The relay took to six world records broken this morning, and 16 overall. The count so far this year is a staggering 67 global standards this year.