The two men differ in age by barely a year but have had quite different careers, Groves winning a world title last year after three times losing with a global strap on the line while Eubank Jr is only just now getting a shot at one.
But they will face familiar foes tonight when they get in the ring together, having previously sparred as many as 300 rounds against each other. There is little doubting that they know exactly who they are up against and don’t appear to like what they see.
Adam Booth, Groves’ coach for six years, was in on nearly all those sessions and reckons the rivalry between the two helped them both.
“I don’t think either of them ever had better spars in terms of the work they got in,” Booth told Boxing News.
“They knew that if they made a mistake they would pay for it.
“There’s only one occasion I can recall when one of them was slightly hurt.
“That was, ironically, when George caught [Eubank] Junior with a left hook and Junior appeared to be stunned.
“There was definitely something that happened in that spar because of that left hook. That was probably one of the last spars they had.
“They did an average of six rounds each time and I’d guesstimate they did that on 30 different occasions. But it might be closer to 50.”
But Eubank Jr showed no signs of fear or nerves when he stared into Groves’ eyes ahead of the weigh-in.
“I told him he’s not ready, I can see it in his eyes,” Eubank Jr said.
“George doesn’t want to be here. I want this more than anything I’ve ever wanted.
“He doesn’t realise the danger he’s in. I am going to knock him out cold!”
Eubank Jr has also told Groves he will send him off to retirement – but the 29-year-old thinks his opponent has underestimated the challenge ahead of him.
“He is that ignorant he thinks he can do it himself,” Groves said.
“‘The cornermen give me water, I do the rest. I train myself, I know what I’m doing’.
“But it doesn’t work. The greatest fighters in the world have a great team or trainer around them just to nudge them in the right direction.
“His dad, Chris Eubank Snr, is supposed to be that, but it’s the blind leading the blind.”