The Belgian Borlee brothers made history on Thursday when all three competed in the 4x400m relay, a first for the world athletics championships.
Twins Jonathan and Kevin, the 2011 world 400m bronze medallist, ran in their heat in Moscow alongside younger brother Dylan, making his world debut, and Antoine Gillet.
It was the first time in the history of the world championships that three siblings had all competed together in the same race.
Jonathan did well to get back into third spot after a poor first leg from Gillet.
Brazil's Wagner Cardoso then overtook debutant Dylan on his third leg to push the Belgian quartet back into fourth, but Kevin produced a strong anchor-leg to get back into third spot, with the top two of the three heats automatically qualifying along with the next two fastest.
The Belgians, who had finished fifth at the 2011 world titles in Daegu and one place lower at the 2012 Olympics Games in London, finished in a season's best of 3min 00.81sec.
The Belgian brothers, whose older sister Olivia won Olympic silver in 2008 and world bronze in 2007 in the 4x100m relay, lived to fight another day as they sealed one of the two fastest losers spots, along with Brazil.
The final of the 4x400m relay will take place on Friday, with the United States, Jamaica, Trinidad and Tobago and Britain among the favourites for the podium.
