So goes one Deep South version of the lyrics still sung in certain parts of America to scare children to bed.

Is the bogeyman coming for Anthony Joshua again on Saturday night?

Actually, the correct spelling is Boogeyman but Andy Ruiz Jr knows exactly who we are talking about.

Andy Ruiz Jr (L) and Anthony Joshua (R) will fight again for heavyweight titles on Saturday

‘I’m not sure if I’m his bogeyman,’ says the Mexican original whose electrocuting speed shocked Joshua into surrendering his world heavyweight titles six months ago.

‘What I do know is that his style is perfect for me.’ Is Joshua spooked? If so it would be unsurprising since immediate rematches do not often turn out well for the loser of the first fight.

There have been notable exceptions but the psychological trauma of a defeat this crushing is usually best treated in the rehab of a couple of faith-restoring routine wins against journeymen.

Joshua is taking this risk to maximise the financial clauses in the contract. So that style may have to change.

He is expected to run in the desert, though, not primarily to hide behind his long left jab. Rather, to elude the volume of quick-fire punches which dropped him four times in seven rounds that midsummer New York evening. So that he might keep going about his work for longer. Perhaps the full 12 rounds.

Joshua showed off his very slimmed-down physique at the weigh-in in Saudi Arabia

The hardest game, this certainly is. But when it comes to the world championship peaks, and despite the crunching blows to the head, at least 80 per cent of boxing is in the mind.

Determining the inner workings of the Joshua brain has been problematic during his transition from four-belt world champion to one-defeat challenger.

At first he seemed in denial. At his Sheffield training camp the week before last he was reflective at times to the point of appearing almost as comatose as he found himself in the Madison Square Garden ring.

What a difference a few days makes.

This Monday the mental batteries were re-energised to the high levels of his Olympic gold and world title triumphs. Thus he found the clarity to express in one emphatic word the situation in which he would find himself should he lose to Ruiz a second time: ‘Catastrophic.’ Little imbues motivation as sharply as honesty.

Joshua is adamant that far from cashing out on his $85 million purse he will box on ‘through another ten years because it’s my life and I love it.’

The British fighter has called upon the services of smaller sparring partners in training

Yet this intelligent being knows that if it does go pear-shaped in that purpose-built arena, then his Saudi investors and luxury brand sponsors might wobble with him, the commercial value of his ensuing fights take a hit as dramatic as those landed by Ruiz, the road back to the summit be as tortuous as the trails across the nearby dunes.

And he is aware that by consensus of the boxing community what he is looking at here is a 50-50 fight, at best.

That judgement is predicated in part on the 6ft 6in Joshua’s aversion to small opponents. Ruiz stands four inches lower and in their first fight he mirrored Joe Frazier bullying in low at Muhammad Ali.

Joshua has been practising, seemingly day and night, at hitting down on a collective of shorter sparring partners.

Then there is the vexed question of speed. AJ the Adonis has shed some of the surplus muscle which weighed on his movement so he should be leaner of physique and lighter on his feet.

Upon receiving that intelligence it would seem Ruiz went into the reverse.  In fact, he weighed in on Friday more than a stone heavier for this rematch.

Ruiz Jnr tipped the scales at 20st 3lbs, more than a stone heavier than the previous fight

If so Joshua must expect to collide once more with a runaway tank with a Ferrari engine.

That presumes, however, that Ruiz has not had the edge taken off him by his sudden wealth and celebrity.

Might he oblige Joshua by going the way of Buster Douglas, who pulled off the upset of last century by knocking out Mike Tyson only to turn up against Evander Holyfield fat and interested only in picking up the money while going down without a fight?

Hasim Rahman, who scored his seismic victory over Lennox Lewis but was flattened in an immediate rematch like this one in the ancient capital of Diriyah, thinks not.

While Rahman admits his own regrets, he says: ‘That is not the way of Mexican warriors. Unless Joshua can bore us all by jabbing and moving all night Ruiz will repeat.’

Ruiz Jr achieved history in June by becoming Mexico’s first world heavyweight champion

Yet while Mexico’s first, albeit unexpected, world heavyweight champion insists he prepared full-out in his California home, British and French television crews report their frustration at his failure to turn up for training there on three appointed filming days in one week. Supposedly stricken by a cold.

Be any of that true or false in his case – and Ruiz may simply have wanted to spar away from prying eyes – Joshua will not have missed a beat.

He says: ‘I feel like I’ve been in a dungeon for weeks and just come out for everyone to judge the success of me as a lab experiment.’

It has been an intense course after the crash.

He explains: ‘For so long I was happily turning up and just knocking people over. Bosh. I didn’t give a f*** about techniques and tactics. So I’ve had to go back to basics, re-learn my craft, immerse myself in the sweet science.’

Principally so that he curbs his hazardous instinct for getting into a street fight if he is hurt. Or, as he did against Ruiz, rush in for the 𝓀𝒾𝓁𝓁 after he had his man down early only to leave himself open to a huge left hook from which he never fully recovered.

If he gets sucked in, the likelihood is he will be blown out. Again.

Nor will he enjoy the inspiring support of the 80,000 crowds who have followed their Pied Piper to Wembley and Cardiff’s Principality Stadium.

The Diriyah Arena in Saudi Arabia has been purpose-built for the fight and is impressive

The 16,000-seat arena is a temporary monument to instant construction but the atmosphere is unlikely to be feverish. With the locals at best curious rather than excited, there is precious little buzz in town.

The hoped-for 3,500 Joshua fans – be they based in the Middle East or en route via party nights in Dubai – must be arriving late.

Every Englishman who is in attendance will be anxious about the potentially overwhelming torrent of Ruiz’s punching. Except one.

Joshua says: ‘I’m never nervous before a fight. I’m cool now because although I applaud him for being the better man on that one night I truly believe I’m the superior boxer and I’m going to win this one.’

TEAM AJ: 1. Robert McCracken MBE (trainer), 2. Tyrone Spong (sparring partner), 3. Ian Gat (physio), 4. Nas Ahmed (logistics manager), 5. Elvis Garcia (sparring partner), 6. Jamie Reynolds (S&C coach), 7. Bryant Jennings (sparring partner), 8. Ben Ileyemi (head of security), 9. Anthony Joshua OBE, 10. Marchello Moore (Andrew Tabiti brother and manager), 11. Joby Clayton (coaching team), 12. David Ghansa (camp manager), 13. Andrew Tabiti (sparring partner), 14. Timothy Moten (sparring partner), 15. Mark Ellison (nutritionist), 16. Angel Fernandez (coaching team)

That confidence is partly rooted in rehearsals designed to prevent him becoming rooted to one spot just in case lightning strikes twice. As it is prone to do when storms swirl across deserts.

So can Joshua hold his nerve and make his height and reach count?

If no, then the nightmare spectre of the bogeyman will return to haunt him.

If yes, he can prevail and move on to another hugely enriching fight against Tyson Fury or Deontay Wilder next year.

And yours truly will have to try to resist the temptation to say I told you so. On points.