OF all the boxers I’ve ever seen spar, none have been tougher than Lithuanian light-heavyweight Sergey Rozvadovskij.

Hands up, chin down, he’d use large forearms to construct an impenetrable wall around his face and then use an unbreakable will to march down whoever was unfortunate enough to be in his way. Unflustered, he did this round after round, never once complaining, never asking for a break or a day off, and if told there was to be a 30-second rest between rounds, as opposed to the customary minute, he offered merely a shrug.

Sergey Rozvadovskij got on with it. He treated sparring as his day job and soaking up the punches of better-known boxers a daily requirement of said job. Even Gennady Golovkin couldn’t put a dent in him.

Which is why George Groves employed Rozvadovskij as a sparring partner for the majority of his fights from 2011 onwards – up until the day Rozvadovskij retired in 2014 – and also why Chris Eubank Jr, a man who has often complained about a lack of willing sparring partners, turned to the poker-faced Eastern European on more than one occasion.

With Sergey Rozvadovskij, you see, they knew exactly what they were getting. They all did.

“I think I sparred Eubank four or five different times,” Rozvadovskij told Boxing News on Tuesday. “We’d do probably six rounds at least each time. With George, I was his sparring partner for almost every fight. I have sparred hundreds of rounds with George.”

Chris Eubank Jnr

This is no exaggeration. In fact, few boxers know more about Groves and Eubank Jr, having eaten up their punches and asked questions of their resolve, than Rozvadovskij.

About Eubank Jr, he says, “He was a good boxer. Compared to most boxers, he is powerful. But compared to George, he’s not so powerful. He’s smaller, he’s definitely a middleweight, and that means he doesn’t hit as hard. But he is fast and he has good stamina. He definitely has good stamina. He could go round after round and not seem that tired.

“He’s also quite awkward. He’s not like a basic boxer. He doesn’t do anything right. But that makes him very difficult to box. You can’t guess what he’s going to do. In the ring, you are thinking, man, he doesn’t do anything from the textbook but it’s f****** working.”

Rozvadovskij laughs. He remembers Eubank Jr’s unorthodoxy and his engine. He remembers the stuff that made him different to the others. Different to Golovkin. Different to Groves. Yet it was nothing to fear, he stresses. The power Eubank Jr possessed wasn’t Golovkin power; nor was it Groves power.

On Groves, Sergey said: “His jab is great, and people talk about that a lot, but with George it’s also about his movement and speed. He uses his legs very well in the ring.

“If he can keep his distance from Chris, he should win. He just needs to keep Chris away. He’s much bigger and he has a much longer reach. All he needs to do is box and keep Chris off. If he does that, he will win the fight.”

It’s not just at long range Eubank Jr needs to be cautious, Rozvadovskij believes. Up close, too, he might find it difficult going about his work without taking an almighty right hand, left hook or uppercut for his troubles.

“I wouldn’t say Chris has the advantage in a fight up close,” says Sergey. “People think that, but George is very good in those areas well.

“Sure, Chris would definitely love to do that, push George against the ropes and in the corners, because otherwise he won’t be able to do anything. I mean, what can he do if it becomes a boxing match? There is no way Chris can outbox George. His reach is smaller. He won’t even come close to George. He won’t be able to land punches unless they are close. He will come forward. That’s a fact. He has to.”

Finally, having remembered all the times they sparred, all the punches given and received, Sergey Rozvadovskij takes a moment to reflect, a moment to think, and then prepares his official prediction, one that should, if you appreciate the man’s history, resonate more than most.

“It will be a unanimous decision for George,” he says, without so much as a shred of doubt. “He will outbox him.”