In the second part of our 2017 year-end review series, statisticians A Lennart Julin and Mirko Jalava look back on the best relay performances of the year.

In the end, after more than three kilometres of running in the men’s 4x800m final, it all boiled down to a sprint – a head-to-head duel between the athletes who finished third and fifth in the Olympic final last year: Clayton Murphy of the US and Ferguson Rotich of Kenya.

An IAAF/BTC World Relays record in the women's 4x200m and yet another dramatic finish in the men's 4x100m were among the key highlights on the first day of the IAAF/BTC World Relays Bahamas 2017, with plenty more drama on tap when competition resumes this evening.

The USA made it a perfect three-for-three in the women's 4x800m, convincingly fending off short-lived challenges by Belarus and Australia who finished second in the opening evening’s first final.

“There are many ways to be a refugee,” says Gai Nyang, a tall, slender 25-year-old from South Sudan. “It’s not about being a victim of a war crisis. Even if you’re out of your country, it’s important that nothing stops you doing the thing you want to do.”

If the brief history of the IAAF World Relays is to be relied upon, then it appears the US, Kenya and Poland will duke it out for the title in the men’s 4x800m final on Sunday night.

While their team may be lacking some of the established star power that propelled them to the title in each of the two previous editions of the IAAF World Relays, USA will nonetheless start as the team to beat in the women's 4x800m, this year's first final.

World U20 champion Kipyegon Bett and Ferguson Rotich, the 2016 IAAF Diamond League winner in the 800m, lead Kenya's 30-member squad to the IAAF/BTC World Relays Bahamas 2017 in Nassau on 22-23 April.

Casimir Loxsom has admitted: “I’m as close as you can be to a 600-metre specialist.”

Statisticians A Lennart Julin and Mirko Jalava look back on the best relay performances of the year.

The fact that USA successfully defended their 4x800m title at the IAAF/BTC World Relays, Bahamas 2015 wasn’t a surprise. But their margin of victory was quite a shock – not least to their opponents.

The first gold medal of the IAAF/BTC World Relays went to the USA whose quartet exuded confidence throughout the race to cross the line in 7:04:84.