Oleksandr Usyk, the world heavyweight champion, carries himself with such a light and humorous touch that it is easy to forget the burden of responsibility bearing down on him. As Ukraine’s war against Russia grinds on, Usyk knows that millions of people are relying on him to spread a rare flurry of good news when he defends his world titles against Tyson Fury late on Saturday night in Riyadh.

Their first fight, in May, which Usyk won on a split decision, produced a battle for the ages, but Usyk has to be prompted gently to discuss the impact of his achievements on Ukraine’s morale. “Of course I was speaking with Ukrainian soldiers, with my friends who are now protecting my country, about the fight,” Usyk says. “I will tell you one story. There is the frontline where the fighting is taking place. And the guys on the second line, they have special communications connecting them to the frontline of the battlefield. They have nicknames like ‘Rocket’.”

Usyk grins as he acts out the conversations on the battlefield after he defeated Fury. “They would be saying: ‘Rocket, Rocket, can you hear me?’ The intonation [of the soldiers called Rocket and other nicknames] was very serious when they first took the phone. They were like: ‘Yes, yes, what’s going on? What do we need to do?’ They were thinking it was an emergency to do with the war but then they got the information that I was the undisputed champion and they started cheering like: ‘Oh yeah! OK!’”

The mood of the country was lifted, at least for a while, by Usyk’s victory. He explains that there was similar joy among his three eldest children who stayed up to watch the fight on television. But, before their father’s narrow win over Fury was confirmed, they went through a real ordeal. “They were very afraid and nervous, my two boys and my daughter,” Usyk says simply. “When I got home they said that I am now a real legend. But I tell them that ‘legend’ is very high-class. I don’t like it. I like to just be a simple guy. I don’t want other people to put me as an icon. I don’t need it.”

In the buildup to the first fight Fury insulted Usyk repeatedly. But he has been notably more respectful since they shared a ring for 12 brutal rounds. “Tyson now speaks less than he used to,” Usyk agrees. “Maybe he has changed. Maybe it’s his game. I don’t really care what he says about me. I have no anger towards him, only respect.”

He also feels compassion for his giant opponent because, rather than just being pure fighting men, Usyk and Fury feel a bond as fathers. Usyk speaks sincerely when he reflects on the fact that, in fight week in May, Fury’s wife, Paris, suffered a miscarriage six months into her pregnancy. “It’s incredibly sad. I pray that everything is fine with them and that it is not a deep trauma that influences their life too much. I wish them all the best.”

Usyk also reflected on his own grief, and the death of his father in 2012, in deeply moving detail in the immediate aftermath of his victory over Fury seven months ago. At 4am that Sunday, with his face marked and scarred by battle, Usyk revealed how his father had visited him regularly in his dreams in the preceding months.

And so, rather than extolling his new status as the undisputed world heavyweight champion, Usyk began to cry softly as he said: “I miss my father. But [in his dream] I say to my father: ‘Hey, listen, you live there …’”

The tears rolled down Usyk’s face as he pointed skywards. “I live here. Please, no coming for me. I love you.”

He now nods at the reminder of his emotions. “Of course he’s still present in my life. It could never be any different after all he did for me. But now he comes to me less in my dreams, or he practically doesn’t come at all, because I said that he shouldn’t. Maybe he will appear closer to the fight. But I remember him, I often think about him, I look at his photos. He’s always with me.”

But Usyk soon lights up again with amusement as he remembers his excitement, and that of his father-in-law too, when Lennox Lewis recently visited his training camp. When Usyk became the first undisputed world heavyweight champion this century he matched the feat Lewis had achieved in 1999. But there is little doubt that Usyk considers Lewis as the real ‘legend’.

“It was so great,” Usyk says of the visit. “Once I watched him fight on TV. Now, Lennox Lewis is in my camp, watching my sparring. I said: ‘Wow! Hey Lennox! You miss boxing, you miss preparing?’ He said: ‘Yeah, of course.’ Listen, it was great to be with him. I got a poster. I said: ‘Hey champ, please will you sign for both of my sons.’ The father of my wife had already said: ‘Oh my God, Lennox Lewis! Please get a signature and a photo.’”

There is not much time left now before he steps back into the ring against Fury – and so Usyk’s smile fades as he contemplates the rematch and explains what he needs to do to achieve another victory for his country and his children.

“I need to be better than I was in the first fight,” Usyk says with winning intensity.