Thompson flew to Kyiv to spar with UsykCredit: Jordan Thompson – Instagram

The heavy-handed Thompson, 30, challenged Jai Opetaia for the IBF cruiserweight title in only his 16th fight. He risked fighting the vastly more experienced champion partly because of his swift progress as a professional, which he recognises owes so much to time spent around Fury and Usyk in Las Vegas, the UK, and Kyiv.

“I got a phone call about sparring Usyk, and I didn’t even think twice,” he told talkSPORT. “I said, ‘Yep, no problem – [it’s] an experience of a lifetime’.

“I was on my own – I didn’t really think about that on my way there. I was staying bang in the middle of Kyiv. The sparring – going into the middle of nowhere; in the countryside; they had three little huts – proper secluded, a real mysterious place. The first spar, we had gone into a little backroom. The ring was tiny. ‘This is going to be fun.’

“The first time I went in for two rounds with him. This was for the [Murat] Gassiev fight [in 2018]. I’m doing my thing, being myself and trying not to get a pasting. I got in some really good rounds with him. He had about four of us there, in and out – a light-heavyweight, cruiserweight, heavyweight, super-heavyweight – so he was getting the rounds in.

“He would do three rounds with the light-heavyweight, three rounds with me, then he’d do three rounds with the heavyweight, and then he’d do three rounds with the super-heavyweight – and then it got on to four rounds each. But then the super-heavyweight – he was actually doing five-minute rounds with him at one point.”

Usyk, then 31, travelled to Moscow – even in the years before Russia’s invasion of Ukraine, tensions between the two countries were sufficiently high that the environment would have been beyond hostile – and proceeded to produce the punch-perfect performance that brought him a wide unanimous decision and one of his finest hours.

“He’s a phenomenal boxer,” Thompson continued. “Phenomenal athlete – he definitely lives the life and he goes about his business very seriously. I’m there shadowboxing, warming up with my bands and that, he’s just stood there juggling balls, and then he’s been doing breathing exercises and stuff like that. What he puts on his social media is pretty much how he goes about his business – he’s a bit of a joker, [but] as soon as he gets in the ring he switches on, and he’s not someone to be played with

“Composure – whether it was mental; physical – [he was] a very, very composed individual, and just very intelligent. He knew what I was doing way before I was doing it. A very, very calculated, smart, smart boxer. He’s all about the hit-and-not-get hit; doesn’t really engage in any unnecessary dust-ups; his footwork for a guy that size is special. He’s a special fighter.”

Thompson sparred Fury in Las Vegas and MorecambeCredit: Jordan Thompson – Instagram

Lewis was the last undisputed heavyweight world champion but the division has not seen one since 1999Credit: Getty

If Thompson’s time around Usyk gave him insights into one of the world’s most admired fighters, by sparring Fury ahead of his two victories over Deontay Wilder – the first fight between them was scored a draw – he perhaps learned even more about one of the most revered of all heavyweights while he remained in his prime.

“He’s a special man,” Thompson explained. “If you’re in the camp, he treats you like one of his own. He takes you in. He really did a lot for me as an individual, and as a boxer. We had some good conversations; he gave me some really good advice; he really goes over and above.

“[Las] Vegas was the first camp for the second Wilder fight. Then we sparred – one little camp – when he was supposed to be fighting [Agit] Kabayel, and then the third fight with Wilder. We spent a lot of time up there as well – we were there for about four or five weeks in Morecambe.

“He made sure we had a car in Vegas; he put us up in a real nice spot; when we were in Morecambe he gave us his own car to drive around in. Not the Ferrari unfortunately. He was always checking in; he was always making sure we had enough money for food; he would hang around and give us advice; speak to us about the sparring. He’d even let us train with the coaches.

“To move the way he does – his reactions; his hand speed at that size; his foot speed – it is second to none. That’s why people speak about him and Usyk – they’ve got a lot of similarities. The ring IQ – they’re very smart; very relaxed; very composed; their footwork; they’re primarily hit-and-not-get-hit.”

Fury and Usyk were first scheduled to fight on December 23, until the 35-year-old Fury’s disappointing performance in victory over Francis Ngannou forced one postponement until February 17, and the cut he suffered in sparring forced another, until May.

“Fury can get you to do what he wants you to do – it’s pretty special,” said Thompson, who after an operation on his hands expects to return to the ring later in the summer. “There’s a method to everything, and again – he’s very, very adaptable.

“With Usyk, we have always seen that he’s a phenomenal, phenomenal tactician, and technical boxer. But with Fury, whatever is put in front of him he’ll adapt to it, and he’ll come up with something to get the win.”