Well that was quick. The 19-year-old uberprospect Moses Itauma has just blasted out Demsey McKean in the opening round. Two heavy knockdowns before the referee waved it off at the 1:57 mark. A statement win for Itauma in what had been thought to be a step-up fight. The boy’s a bit special!

Donald McRae

It’s a quarter to one in Riyadh as the crowd awaits the co-main event. Here’s a dispatch from Donald McRae, our man at ringside:

It’s 12.45am in the Kingdom Arena and there is a real bite to the air. It feels like we are outside rather than near ringside in this vast indoor auditorium. For a while, during the slugfest between Johnny Fisher and Dave Allen, it was akin to hanging around a pretty cold carpark at the back of a McDonalds watching two small town bruisers having a roundhouse swinging dust-up. I’m not sure Fisher v Allen was quite what the Saudis had in mind when they decided to take over boxing. It was crude stuff but Allen really should have won by stoppage … he let it go to the judges and two of them robbed him.

The atmosphere is muted as Ishmal Davis fails to come out for round seven. Serhii Bohacuk was simply too much for him.

I am looking forward to a little more heat, and just one more fight, before Usyk v Fury …

Serhii Bohachuk has defeated Ishmael Davis after Davis’s corner threw in the towel after round six. It’s a good stoppage after the Leeds man was dropped once and took a one-sided beating over the next four rounds. That means Bohachuk is the mandatory challenger for Sebastian Fundora’s WBC title at 154lb.

Oleksandr Usyk and Tyson Fury are expected to make their ringwalks around 2am local time (11pm GMT and 6pm ET). Here’s how they measure up ahead of tonight’s main event. Fury came in at a career-high 281lb at yesterday’s weigh-in at the Kingdom Arena while Usyk tipped the scales at 226lb, making for a yawning 55lb discrepancy that will be slightly reduced in the ring. Fury’s advantages of seven inches of reach and six inches in height remain the most imposing physical obstacles facing Usyk, the former undisputed cruiserweight champion who has exceeded all expectations in six fights at heavyweight.

Weigh-ins ahead of heavyweight fights are almost entirely ceremonial affairs since it is the only weight class where fighters aren’t bound to meet a contracted pound limit. But Friday’s proceedings were of particular interest given the extent to which each man’s weight affected their performance in their first meeting. Our Donald McRae was in the room:

It had been widely expected that Fury would come in much heavier for the rematch. But the extent of the weight disparity was still surprising and it offers the most graphic indication yet that Fury, as he has promised all week, will be intent on walking down Usyk in the belief that the former world cruiserweight champion can be stopped by sheer physicality and bludgeoning force.

Fury is also six inches taller than Usyk. Carrying so much weight, he will not be looking to dance and move fluidly across the canvas. He will lean down heavily on Usyk, trying to drain him of energy – and of course he will plant his feet and, with aggression and power, look to blast his way through the defence of the brilliant and intelligent Ukrainian. Usyk is a master strategist and Fury has told him clearly what he is about to confront. The unbeaten champion is never intimidated in the ring and he will be ready for Fury’s coming onslaught.

Hello and welcome to tonight’s heavyweight championship rematch between Oleksandr Usyk and Tyson Fury. We’re back at Riyadh’s Kingdom Arena seven months after Usyk toppled Fury to become the sport’s first undisputed heavyweight champion in a quarter-century. Will the 2012 Olympic and two-weight champion from Ukraine double down on his supremacy in boxing’s prestige division? Or will it be 2 Fury 2 Furious as the Gypsy King restores his place atop the heavyweight throne?

Of the many well-documented reasons for boxing’s protracted retreat toward the periphery of the mainstream, the lack of clearly identifiable champions rates high on a competitive list. At one time the heavyweight championship of the world was the most prestigious title in sports, yet the lack of central authority has left us with four major sanctioning bodies that have generally created confusion among casual observers while devaluing the currency of a title.

Usyk delivered that long-sought clarity in May when he won a razor-thin 12-round split decision to add Fury’s WBC title to the WBA, IBF and WBO straps he’d won from Anthony Joshua, making him the first boxer to hold all the major belts at the same time since Lennox Lewis.

Because we can’t have nice things, tonight’s rematch is not for the undisputed title. That’s because Usyk generously vacated the IBF strap in June so it could add some juice to the Daniel Dubois-Anthony Joshua show at Wembley in September. (Dubois won that fight and the belt by fifth-round knockout in an upset.)

But make no mistake: these are the two best heavyweights in the world today … and Usyk is the one and only true heavyweight champion. How will he fare in his first title defense? We’re roughly two hours from finding out.