The United States of America dominated from start to finish to win the final event of the 12th IAAF World Junior Championships, the men's 4x400m relay.
The combination of Marcus Boyd; Bryan Miller; O'Neal Wilder; Jeshua Anderson, in running order took victory in 3:03.86, the best time by any Junior team this year.
Boyd led off with 44.87 to Miller, who split 48.42 before third leg runner Wilder and anchorman Anderson completed the race with 46.15 and 46.16 respectively.
Boyd said: "I was tired from the four prior races, but I did my best and managed to put the team into the lead."
Miller added: "I ran the best I could to keep the lead," while Anderson said: "I just needed to relax and take my team home."
Great Britain finished second in a season best 3:05.82 while Germany ended third, also in a season best 3:06.47.
Bahamas who was still in contention after the first leg, lost all chances of a medal as Jeffrey Gibson fell heavily on the floor with 150 metres to go.
Anthony Foster for the IAAF