Vasyl Lomachenko meets Britain's Luke Campbell for the former's World Boxing Organisation (WBO) lightweight belt and the vacant World Boxing Council (WBC) title.

Such close encounters have been infrequent since the days when Muhammad Ali, George Foreman and Joe Frazier mixed and matched in the seventies. Most observers see Saturday (August 31) as an easy night's work for the first UK appearance of the Ukrainian superstar now regarded as the world's supreme pound-for-pound protagonist.

Both are 31, but Campbell, despite his own Olympic status from London 2012, is not quite in the same league as the man from Bilhorod-Dnistrovskyi (there's one for the ring announcer to get his tongue around), though conceivably he might do a tad better than the last Briton to face 'Loma'. Anthony Crolla was dispatched in four rounds by the 2008 Olympic champion. But Campbell will still do well to reach the halfway mark in this 12-rounder.

Huge upsets – even miracles – do happen in sport. Just ask Ben Stokes and the England cricket team. And in boxing you need look no further than the fate which befell the other British Olympic champion from 2012, Anthony Joshua. 

His four world heavyweight title belts unravelled with him as he crashed to the canvas, astonishingly upended by the tubby, unpretentious Mexican-American, Andy Ruiz Jnr, a couple of months ago. Hitherto the much vaunted and unbeaten Joshua had been somewhere around 25/1-on to keep the four crowns he had accumulated in his 23-bout pro career.

Joshua was dumbfounded at the time, but has since regained so much self-belief that he talks as if he is still champion and assesses the shock result as a freak that could never happen again.

He seems disturbingly full of himself in his quest to regain his titles in a rematch bizarrely set in the shifting sands of Saudi Arabia on December 7. Joshua even dissed the great Lennox Lewis as "a clown" when the former Olympic and world champion suggested he might change his training routine.

"Lennox is a clown," AJ proclaimed. "I don’t respect him. We are cut from a different cloth," he sniffed in a Sky TV documentary.

Lewis also scorned Joshua's own suggestion that he was caught by a "lucky punch" at Madison Square Garden. Joshua dropped Ruiz in the third round before walking on to a left hook from which he really never recovered. "I can’t look at that fight and agree that AJ was fully prepared," Lewis tweeted, while suggesting that Joshua should consider altering his training team.

Joshua has always denied there were any issues with his preparation and claimed his defeat was brought about by a "punch sent by the gods". I am among those who agree with Lewis that it was not so much a lucky punch, as a perfectly delivered one which an out-of-sorts Joshua did not see coming.

Joshua also says now that while Ruiz is a good fighter, "he ain't that skilful". Well, he could've fooled us. He certainly fooled AJ, and it was only the second time Joshua had been on the floor as a pro – following that knock-down against Wladimir Klitschko, another fellow Olympic champion, at Wembley in 2017.

These days it is virtually impossible for anyone but sponsoring Sky TV to get to Joshua; he has surrounded himself with a veritable posse of managers, minders and mates who form an even bigger entourage than the one which accompanied Muhammad Ali. Joshua also suggests there is an element of jealousy from Lewis because of the money he has earned (around £60 million so far is the estimate).

Yet if anyone has cause to be jealous, surely it should be Joshua himself, who must be somewhat envious of the way fellow Brit Tyson Fury has overtaken him in the popularity stakes.

Fury's astonishing comeback from a state of mental turmoil is as remarkable as Joshua's defeat by Ruiz. The self-styled 'Gypsy King', who had to forfeit his world title because of a drugs issue, has re-established himself as the 'People's Champion' following his epic draw with WBC title holder Deontay Wilder, although Fury appeared to have done enough to win. 

It is noticeable that Fury puts himself about among the fans, whereas Joshua, protected by his managerial moat, has become somewhat remote. He must also know that if he loses again to Ruiz – who is no slouch as a slugger – he will be finished as a marquee attraction, selling out arenas such as the O2 and Wembley Stadium.

Up to the Ruiz contest, Joshua had been something of a lucky fighter, both in the Olympics and as a pro. He has also avoided a unification bout with the big-hitting Wilder, who scoffed: "He wasn’t a true champion. His whole career consisted of lies, contradictions and gifts."

A somewhat unfair condemnation. But now other big names in boxing, such as American promoter Bob Arum, believe Joshua has made a mistake in taking an immediate rematch with Ruiz rather than a warm-up bout. He might well find the invigorated Ruiz again too hot to handle on those burning sands.

Shooting his mouth off, dismissing his defeat by Ruiz as a lucky punch and demeaning a legend like Lewis won’t endear him to the fans either.

Joshua may or may not need to change his training routine, but he certainly needs a change of attitude.

Arrogance will not win him back his world titles. A little humility and a lot of hard work might.