It may not look as spectacular as the pole vault or as turbo-charged as the 100m, but there are few disciplines in the Wanda Diamond League which offer the sheer psychological drama of the 5000m.
The 12-and-a-half laps are not only a test of endurance and a delicate balance of speed and stamina, they are also a tactical minefield, where one false step at the wrong time can prove fatal and potentially career-defining decisions have to be made in the heat of the moment.
"The 5000m is all in the mind," says 2020 Olympic bronze medallist and 2018 London Diamond League winner Paul Chelimo. "It's only about 75 percent fitness. The rest is mental."
Chelimo knows as well as anyone just how dramatic the 5000m can be. In the 2017 Diamond League Final, he played a starring role in one of the most legendary 5000m races in athletics history, when British rival Mo Farah won his last ever track race in a jaw-dropping photo finish.
Farah's win gave him the first and only Diamond League title of his career, and it took as much out of him as any of his major championship gongs, as Chelimo and Muktar Edris hounded him down the home straight and came within millimetres of catching him as they tumbled over the finish line.
Watch: Mo Farah's 2017 Diamond League title win in Zurich
At that stage of proceedings, it's all about firing on all cylinders, says Chelimo. But to get into a winning position in the first place, you have to weigh your race perfectly and pick your moment with care. And that is more of an art than a science.
"You never know what to expect. You don't know when somebody is going to make their move," says Chelimo. "What do you do if someone moves with a mile to go? Do you follow that pace or go at your own pace?" If you do one, he explains, you risk falling behind the pace at a key moment. If you do the other, you might burn out too quickly.
And there are other variables. "What do you do when someone obstructs you in a race? How do you prepare for that? How do you make a move? How do you separate yourself from 10 people at the finish line? I'm a professional, but I'm still learning," says Chelimo.
So if the 5000m is a moveable feast, how do you set your own tactical approach. Chelimo breaks the discipline down into several, ever more intense phases.
"As soon as the gun goes, I try to stay with the leaders. If the pace is too slow, I try to control the pace," he says, adding that the key moment comes after the 3000m mark."
"After the 3k, when the pacemaker drops out, you don't know what move someone is gonna make," he says. This is where picking your moment is so crucial, in order to make sure you are still in the running at the business end of the race. At that point, it's all or nothing.
"The last two laps is where the race is decided," says Chelimo. "In the last 200m, you take off the safety belt. Go hard or suffer."
