Jamaica, USA into 4x200m final as Kenya win men's 4x800m
Jamaica's Warren Weir reacts after the men's 200 metres event at the 2013 IAAF World Championships at the Luzhniki stadium in Moscow on August 16, 2013 - by Olivier Morin
Weir anchored home the foursome that also included Rasheed Dwyer, Jermaine Brown and Jason Livermore, with the final scheduled for 0015 GMT.
The Jamaicans clocked 1min 20.15sec to finish ahead of France and St Kitts and Nevis.
In an electric atmosphere in an almost sell-out 15,000-seater Thomas A. Robinson stadium, the Bahamaian quartet could only finish fourth, but qualified for the final as one of the two fastest, along with China, outside the top three in each heat.
The United States, anchored by Wallace Spearmon, coasted home to win their heat in 1:21.35.
There was a similar story in the round one of the women's 4x100m, the US and Jamaicans advancing smoothly from their heats in the same time of 42.29sec to the final, set to round off the first day's action at 0042 GMT.
The first gold medals of the inaugural IAAF World Relays, launched to boost interest in track events among a younger audience, went to Kenya in an unexpectedly dramatic finish in sultry conditions.
Ferguson Cheruiyot Rotich, Sammy Kibet Kirongo, Job Koech Kinyor and Alfred Kipketer covered the eight laps of the blue track in 7min 08.40sec in a gun-to-ribbon victory in the 4x800m.
As carnival dancers writhed to the beat of a military brass band, Rotich shot Kenya out to a 50-metre lead, American Brandon Johnson doing his best to cut the deficit on the third leg.
Kipketer had it all to do on the final leg, but after accelerating away too quickly, faded badly on his second lap to just scrape home, 0.29sec ahead of Polish anchor Adam Kszczot, the world indoor silver medallist.
The USA team took bronze with 7:09.06.