Shelly-Ann Fraser-Pryce anchored Jamaica to a world-leading 41.84 in the heats of the 4x100m relay in Saturday’s morning session.
Although the heats were scheduled at high noon, the shoot-out will come in tonight’s final, when Jamaica will face off with the USA, who won the second heat in 42.00.
National records and season’s best peppered the heats, Canada, Trinidad and Tobago and the Netherlands all improving their previous marks.
Barring disaster – always just around the corner in relays, of course – the two powerhouses of Jamaica and the USA look certain to fight out the gold medal. The USA won in a world record at the London 2012 Olympics. Jamaica triumphed in a championship record of 41.29 in Moscow and won at the IAAF World Relays earlier this year.
Both teams looked slick enough in the heats, though it remains to be seen what will happen with the added pressure of the final.
Sherone Simpson led off for Jamaica in heat one, followed by Natasha Morrison, Kerron Stewart on the bend and then Fraser-Pryce to bring it home. Who said the top sprinters do not like to run morning preliminaries?
Jamaica had almost six metres to spare over second-placed Great Britain. Asha Philip, Jodie Williams, Bianca Williams and Desiree Henry got the baton around in 42.48, their country’s fourth-fastest clocking ever.
Canada took the third automatic qualifying place with a national record of 42.60. Crystal Emmanuel led off, followed by Kimberly Hyacinthe, Isatu Fofana and Khamica Bingham.
Russia, fourth in 43.09, qualified as one of the fastest two non-automatic qualifiers.
Allyson Felix ran the back-straight leg for the heat-winning US squad. English Gardner started, Jenna Prandini took the second bend and Jasmine Todd brought the baton home.
The result was a little closer than the first heat. Trinidad and Tobago took second place in 42.24, Kelly-Ann Baptiste starting, exchanging to Michelle-Lee Ahye, then Reyare Thomas and Khalifa St Fort.
The Netherlands was third in 42.32. Dafne Schippers, who won the 200m on Friday night, ran the back-straight leg, receiving the baton from Nadine Visser. Naomi Sedney ran the bend and Jamile Samuel the anchor.
Germany, fourth in 42.64, also advanced to the final as the fastest non-automatic qualifier.
Len Johnson for the IAAF