It wouldn't be going out on too thin a limb to say that the women's 4x400m at this weekend's IAAF World Relays will come down to a battle between USA and Jamaica. The two powerhouse nations have finished 1-2 at all but one major global meeting since the 2012 Olympic Games; there's little to suggest a different outcome in the penultimate final on Sunday's programme.
The USA has beaten their Jamaican rivals into second at both the past two Olympics and at both editions of the IAAF World Relays. The lone exception came at the IAAF World Championships Beijing 2015 where Jamaica got the edge courtesy of Novlene Williams-Mills who overtook Francena McCorory in the final metres to win by just 0.31.
Neither will return to team duty this weekend on squads that appear quite evenly matched, with recent momentum perhaps favouring the North Americans.
The US pool includes heavy hitters Ashley Spencer, Natasha Hastings and Phyllis Francis. Spencer is a 4x400m world indoor gold and silver medallist, world indoor 400m runner-up and Olympic 400m hurdles bronze medallist. Hastings, 30, is one of the squad's most decorated relay runners, with two Olympic, three world indoor and three world outdoor relay gold medals in her voluminous vault. Francis, 24, raced her way into the 2015 world and 2016 Olympic 400m finals. They'll be joined by Quanera Hayes, the early-season world leader at 50.04.
Jamaica will come armed with most of their stable's best, including Shericka Jackson, Christine Day, Anneisha McLaughlin-Whilby and Stephenie Ann McPherson, all of whom have earned medals in the event on the global stage indoors, outdoors or both. Jackson, the youngest on the squad at just 22, already has world and Olympic bronze in the 400m to her name and is a member of the world champion 4x400m squad.
In most cases in recent years, it's been a British team that fills out the podium after the big two. That's a likely scenario again this year with the Olympic bronze medal-winning quartet of Eilidh Doyle, Emily Diamond, Anyika Onuora and Christine Ohuruogu reuniting to carry the baton in Nassau.
The Bahamas meanwhile have entered the athlete who is, at least as far as the host nation is concerned, the weekend's star attraction: Olympic 400m champion Shaunae Miller-Uibo. She'll team with Anthonique Strachan, the 2012 world U20 100 and 200m champion, but her better chance at a medal – or even victory – this weekend will come in Sunday's evening-capping mixed 4x400m.
On certainty: with the top eight teams earning automatic entry into this summer’s IAAF World Championships London 2017, competition will be fierce.
Bob Ramsak for the IAAF