The United States won the women's 4x400 metres relay by some distance at the London Olympics to give Allyson Felix her third gold medal of the Games.
Felix, who won the 200 metres individual title and was part of the 4x100m team that smashed the 27-year-old world record on Friday, ran the second leg as the Americans crossed the line first for the sixth successive Olympics.
There was to be no world record in the one-lap relay with Sanya Richards-Ross, the individual 400 metres champion, crossing the line in three minutes 16.87 seconds, outside the mark of 3:15.17 set by the Soviet Union at the 1988 Seoul Olympics.
Russia finished second for silver in 3:20.23 and the bronze went to Jamaica who ran 3:20.95.
Team GB were always up against it after starting in lane nine, and in the end finished fifth.