Here Planet Sport analyses the two fighters ahead of their rematch.
Pound for pound contender Usyk has been described as a "genius" by promoter Eddie Hearn and it is hard to disagree.
An awkward southpaw counter-puncher, the 35-year-old former undisputed cruiserweight world champion has speed on his side. He is technically brilliant, has excellent ring IQ and moves with agility.
Joshua throws high-quality shots and has power in both hands, but his straight right is his most devastating weapon.
A key strength against Usyk will be his superior size and strength that he must leverage at close quarters.
Joshua knows he cannot win by using the same tactics that led to his downfall in the first fight.
His attempt to outbox the skilful Usyk was baffling, he failed to capitalise on his size advantage and he was surprisingly passive.
New trainer Robert Garcia has been recruited to oversee a more aggressive approach, mentally and physically.
Usyk's weight is less than a pound heavier than for the first fight and there are unlikely to be any major changes in the knowledge he has Joshua's number. His focus in the early rounds will be on adjusting to what his opponent brings this time.
Not much has changed in this respect with Joshua retaining close to a two-stone advantage.
A curious feature of the build-up has been the discussion over what appeared to be Usyk's meatier frame, but when he stepped on to the scales only a nine-ounce increase showed up.
Even Joshua had been lured into talking about what a more muscular Usyk meant, but instead he will face the same cat-like reflexes and ring dexterity.
At three inches taller and with a four-inch reach advantage, the Briton will be looking to impose his physicality.
Joshua has cut an edgy figure all week and the nerves were evident again at Friday's weigh-in.
With a defeat having the potential to end his career, the 32-year-old has asked to be judged on what happens on Saturday night and not any talking during the week.
Usyk, meanwhile, has displayed a steely resolve punctured by moments of humour. If he is nervous, it certainly is not obvious.
The great unknown is how will he deal with the expectations of a Ukrainian nation looking to one of its favourite sons for inspiration while Russia lays siege to their homeland.
The fight is available to the entire country on free to air TV - now Usyk must rise to the occasion.
Usyk to win in rounds 9-12