By Mitch Phillips
TOKYO (Reuters) -The United States, winners of nine of the last 10 world 4x400 men's relay golds, failed to reach the final on Saturday after trailing in sixth in their heat - though they are likely to appeal after being obstructed during a takeover.
The U.S. have a painful history of foul ups in the sprint relay but rarely have any problems in the 4x400 and have won winning 12 of the 19 previous finals.
However, they struggled to impose themselves from the start on Saturday. They
were back in the pack after the first two legs and a clash with the Zambians at the second changeover made it even worse. By the time Jenoah McKiver collected the baton for the anchor leg he was in last place.
He initially made up plenty of places but had gone off too fast and faded back to sixth as an impressive South Africa and a surprising Qatar led the way home.
Botswana, the Olympic silver medallists, had three finalists in the individual 400m final on Thursday, though gold medallist Busang Collen Kebinatshipi was rested from the heats.
Their quartet were still strong enough to win the second heat ahead of Belgium and Australia, who set an area record, but were then disqualified for an illegal changeover.
The U.S. had no such problems in the women’s event, emphatically winning their heat as they bid to regain the title after being dethroned from their usual top step by the Netherlands in 2023.
Even without rested superstar one-lapper Sydney McLaughlin-Levrone, they posted a world-leading 3 minutes 22.53 – marginally faster than Jamaica, winners of the first heat.
The Dutch, resting 400m hurdles champion Femke Bol, also went through.
Norway ran a national record 3:23.84 to progress in second.
Britain have won silver or bronze in nine of the past 10 world championships but were never in contention in the first heat, finishing last.
Both finals take place on Sunday, the last night of the championships.
(Reporting by Mitch Phillips, editing by Ken Ferris)