It's time for Tyson Fury to get serious. Both metaphorically and physically. For one reason: the Gypsy King's return against incumbent champion Oleksandr Usyk has become the most important fight of his career. Indeed, the most important fight Fury will ever have. We know it; he knows it, even though he might not acknowledge it publicly.

Yet there has been that aura around him in these last few weeks before globally anticipated rematch. No signs of cracking, of mental malaise, just a mood. A reticence with words. It feels powerful. It espouses a lack of nerves, too. Just a focus on righting the wrongs of a fight which saw him complacent, arguably, after seven rounds.

Arguably, moreover, Fury was 5-2 up in rounds during that first brutal dance; one for the ages.

Fury has always taken it upon himself to sell fights - from the days of David Haye, Dereck Chisora, through the Wladimir Klitschko era, and in his second period as a heavyweight king, tearing into Deontay Wilder with rawness and an edge-of-the-cliff craziness in those three memorable fights across The Pond in the United States.

There are no more media tales to be told - outrageously saying that he was masturbating seven times a day, or that he had been dipping his hands in petrol, a myth invented that he told me some time ago to toughen up his hands - there is no need now to be the entertainer, the loudmouth, the jester. No need for the Batman suits, the japery, or even mind games.

The only mind he needs to focus on is his own. And it does look like he has gone that way in camp in Malta, in the Mediterranean. Sparring partners - such as Kevin Lerena - have told me that Fury "is sharp, very sharp" in sparring and he will need to be in this second encounter with Usyk, that may well be as close, and taxing, as the first twelve rounds that they danced with each other, in a supreme match-up of fistic chess, of genuine Sweet Science. Usyk, many sages are saying, steps in as the favourite, and knows he can wobble Fury.

But we shall see if a fallen Fury will come back differently. There is another epithet - they say that a happy fighter is a good fighter, but I'm happy that Fury has his grumpy face on right now. That has been my experience of him leading into this fight week in Riyadh. He's not angry, either, not hellbent on revenge, just irked by too many questions. He has enough in his own mind. The test is there; he is coming back from his first defeat. The return fight, the chance to silence doubters, and any doubt in his own mind. The greatest have been through this challenge. Muhammad Ali, and Lennox Lewis to name but two. This is the Fury I want to see stepping in to face his nemesis Usyk for the 'Reignited' showdown on Saturday night.

I have known Fury since his debut in Nottingham in 2008, on the undercard of Carl Froch versus Jean Pascal, a war won by the Briton for the WBC super middleweight title. I have been to his hometown to see him, organised a gathering for him to receive his Ring Magazine belt, travelled to spend time with Tyson and his father John in caravans in the north of England, and been deep in camp with him across America. I have also been in his dressing room three times, interviewing and recording Fury just before his walk to the ring, in London and Los Angeles.

The Fury devoid of jokes, of taking the mic, replenished with focus and with his mindset on doing a number on the exquisite southpaw mover who proved to be his undoing in those eighth and ninth rounds, notably, in their first encounter back in May, offers a fascinating study. They say the best camps are like going into jail. His team has told me that it has been so in Malta, away from prying eyes, and interviews. Away from social media.

Other greats have said the same. "It's lonely," famously said the late, great 'Marvelous' Marvin Hagler, of his training camps. It was spot on, this analogy. "The point of the training camp," said Hagler, "is to get away. It's like putting yourself in jail. It's not a question of liking it. It's a question of having to do it." Training camps should be Spartan. By definition. They should not be about being civilised. They should hone you for battle, away from the family, from comfort, from love. They should be regimented for battle. That has been borne out in recent weeks.

Even Paris Fury, Tyson's wife and the mother of their seven children, has spoken of the hardship of bringing up their children without their fighting father around, while he is away in camp. We sympathise, of course, but in boxing terms, it is a gratifying message. It speaks of a truth. It means that the Gypsy King, the man who must step into the ring, has taken his responsibilities fully upon himself, as he seeks to take his Ukrainian rival's unbeaten record, and put himself back at the summit of the heavyweight division. Back as the king in this game of thrones. There was no other way.

As the great Chinese war tactician Sun Tzu once wrote in his fabled 'Art of War' -- "If there is disturbance in the camp, the general's authority is weak." The general, the Gypsy King himself, appears to be marching with his own authority, and lack of distraction, to this second battle.