Those who have succumbed to the Ukrainian master's technical wizardry not only include Anthony Joshua, Derek Chisora and Michael Hunter but also the best cruiserweights on the planet, Tony Bellew, Murat Gassiev and Mairis Briedis among them.

Even as an amateur boxer he was exceptional, winning world championship and Olympic gold medals.

So far no pro boxer has managed to unpick the particular set of challenges Usyk presents. But Anthony Joshua tries again in a high-stakes rematch tonight on Sky Sports Box Office.

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Victory will restore his place at the top of the heavyweight division, while a second consecutive defeat would be a hugely damaging blow.

What then must Anthony Joshua do to break the aura of invincibility that Usyk has weaved around himself?

1. It starts at the feet

It's natural for the eye of the observer to be drawn to the punches that Anthony Joshua typically lands with such crashing force. But watch the feet. Footwork will be where this fight will be won and lost. That's where Usyk has been so effective, particularly as a southpaw, leading with the right rather than the left hand.

Delicious Orie, the new Commonwealth super-heavyweight gold medallist, who's sparred Joshua, explains, "It's that extra step. You've always got to think where your feet are in boxing but you don't really think about it against a style that you're used to. For example, almost everybody's an orthodox.

"But with a southpaw you've got to think where your feet are positioned because where your feet are positioned plays a massive part in if you connect to hit the target.

"When you've got that extra step and that extra thing to think about, it kind of slows you down, makes you a little bit less responsive to what's coming or what you need to do.

"When I boxed a guy from Uzbekistan, southpaw, a similar style to Usyk, it was the feet. Whenever my lead foot was inside his front foot, I was more susceptible to getting tagged. Whereas whenever my lead foot was outside of his, I could catch him and I was catching him with right hands and my jabs."

That though can be worked on in sparring. Joshua has had a long camp for this fight and plenty of southpaw sparring partners. Being more settled boxing against that stance will be crucial.

2. Make the jab a weapon

There are different jabs. The lead hand can be used as a range finder, a tool to make space, a feint, a way to set up other shots and more. But it can also be a weapon in itself, especially when thrown hard while advancing.

"With the jab, they need to have a lot more authority behind them, let him know he's in with a heavyweight," Orie said. "There's something extra to think about and that stops them from doing what they want to do. That's how you get the edge.

"There were spurts in that fight where Usyk was on his front foot and Joshua was on his back foot so for me that's the biggest thing I feel needs to change. For me that comes from mentality, if AJ comes in there with this thing of I'm the heavyweight, I'm the big man, I'm the strong man."

Orie knows first-hand from sparring that Joshua has a good jab. "The first thing that struck me was how quick his jab was. You look at him, he's a big man," he said, "I would have expected to see his jab coming a little bit more. That's what struck me, how quick he threw his jabs out. There were times when I wouldn't even see it and he would throw it.

"That was the biggest surprise for me with AJ."

3. Punch him in the chest

It's not typically an effective shot, so might seem a waste of time, but the ploy can pay off as Joshua seeks to stymie Usyk's work.

Former world title challenger Matthew Macklin explains: "The key for me for Anthony Joshua is to keep it simple. We know when they get up close, the shots, the drills, the left hooks to the body, head, that type of stuff on the inside that will all flow.

"Getting there is the key. As he approaches Usyk the lead hands will cancel each other out a little bit. I'd just double up on that jab and drive the right hand into the chest.

"Usyk, who likes to lean back and pull and do all this, he won't be able to move his chest. If he drives it into his chest, it pushes, [Usyk] will go off balance, fall backwards and then AJ can step to him again. Now he's putting him under pressure, now he's bossing it."

4. Method to the clinch

It sounds contradictory to say that clinching can be a tool in a boxer's offensive armoury. Boxers typically hold on in a clinch to gain some respite, whether it be from exhaustion or punishment. But for a tall fighter especially, clinching, leaning on and leaning down on an opponent's neck and shoulders can drain them of energy over the course of a 12-round fight.

It was something that Joshua did not do effectively in the first fight, but Usyk should be aware of it for the rematch.

Dave Coldwell, who trained Bellew for Usyk, pointed out, "Look at how Lennox Lewis nullified Mike Tyson early on. No matter about Tyson's age, early on he is so dangerous. So all Lennox did to start off is shut him down, nullify and tire him out by leaning on, leaning on, leaning on. It takes the legs away. It takes the strength away. If you are doing that with someone that relies on foot movement, you're giving yourself all the chance in the world down that stretch.

"When I watched the [first] fight the most shocking thing for me was after few rounds in the clinches it looked like it was AJ that was holding on. He was the one that wanted to just switch off and have a rest," Coldwell added.

"That's basically trying to have a rest mentally. Because the mental side tires out first, then his body started tiring out. Because you're fit, because you're doing all this training you're not unfit, but once your mind starts getting tired, your mind starts thinking you're tired, then your body reacts to it."

5. Be an educated bully

Lawrence Okolie is the reigning WBO cruiserweight champion. He warns against discounting Joshua's physical advantages.

"I think really using the fact that he's a strong talented heavyweight, working the body from round one relentlessly and just mixing it up more. Obviously box in space but not giving him any shots unanswered. So every time Usyk would throw, throw one to the body, throw one to the head. Just really show him he's in a hard, hard fight. Hopefully the size and power will break him down," Okolie said.

"I think it's more intent. No matter what AJ is a good boxer, so watching the first fight it was competitive. It wasn't like it was a one-sided beating or anything, it was a competitive fight and I think adjustments with more intent behind the punches [will work]."

It's an approach former cruiserweight champion Johnny Nelson also endorses.

"Typically a bully uses his size, uses his strength, uses what's natural to him," Nelson said. "Doing that fighting Usyk, he's got to not second guess his shots, he's got to let the shots go. Because that split second when he thinks about the shot, Usyk will pop him.

"AJ has to hit and push, lean, work him out that way. That way he's making Usyk feel very uncomfortable. Make him work at a pace he's not used to working at. What he'll do is try and get space so he can control the pace. If you look at AJ's physique, he's slender, he's streamlined. He's there for the speed. He's there for the power. It's about mentality, he has to walk in, bully and work him out that way."

Can he do it?

This handy five-point plan is more easily written than done. But while Usyk goes in as the favourite, Joshua has plenty he can change after the painful experience of their first encounter.

"Usyk has won Olympic gold, cruiserweight undisputed and beaten AJ off of what he does all the time and I don't see him being able to change it, or wanting to change it," Okolie notes.

"AJ's shown aggression, backfoot boxing, a whole bunch of different styles when he needs to so I think he has the opportunity to adjust more."

Delicious Orie also points out that Joshua is a special fighter himself.

"Anthony Joshua started boxing at 18-years-old and became Olympic champion [just before he was] 23. Who does that? He's at the top of his game and he's very, very good. Usyk is another great fighter," Orie said.

"Whatever happens AJ should always be a top-ranked fighter because he deserves it with what he's achieved already so far."

However it plays out, Usyk-Joshua 2 is likely to be a special fight too.

Anthony Joshua's huge heavyweight rematch against Oleksandr Usyk is on Saturday August 20, live on Sky Sports Box Office. Book Usyk vs Joshua 2 now!