The 40-year-old recently said he has "lost a step", strengthening the conviction of those who believe McGregor capable of an unlikely victory, even while others remain adamant he is simply selling Saturday's fight.

Chris Eubank Jnr has spent the past three weeks training alongside Mayweather in preparation for his World Boxing Super Series quarter-final with Turkey's Avni Yildirim in October, doing so for the third time.

He previously observed the American while he trained to defeat Marcos Maidana in 2014 and then Pacquiao the following year, when Mayweather produced a seamless victory against a fighter widely considered his greatest threat.

The 27-year-old Briton also believes Mayweather will show an increased aggression against Ireland's McGregor, in pursuit of a knockout victory in his final fight, and he told Press Association Sport: "McGregor's got it all to do on the night.

"Mayweather's in just as good a shape as he was against Maidana, and when I watched him train for Pacquiao.

"I don't see any real difference in his preparation, his fitness. He's not taking this lightly. McGregor doesn't have a professional fight but I don't believe that's in Floyd's mind, he's going in there like this is going to be one of his toughest fights.

"With him, the main focus for this camp has been fitness. We're going to see the same Floyd we've been seeing, but a more aggressive Floyd.

"From what I've seen and how I've heard him talk, he wants to put on a show. With the 8oz gloves, he's going to go for the knockout. I just have a feeling, he wants to make a statement.

"This really is going to be his last fight, he wants to go out with a bang. Who wouldn't? I don't think he'd want to end his career on another points victory. So if he sees an opportunity, if he gets a chance, he's going to go for it and try and take Conor out.

"All I can go on is what I think Floyd's going to do: be aggressive, look for openings, look to take Conor out fairly early. If I had to put money on it I'd say he's going for the stoppage. He's extremely accurate, extremely good defensively. If he catches Conor, he could be in some trouble."

In the same way Mayweather has spoken of being in decline, McGregor has insisted he has the power to stop him and inflict the first defeat of his professional career.

Eubank Jnr believes the Irishman's only chance of victory is to retain that confidence, but he said: "People love to say it only takes one punch, and that's true to an extent, but if you look at a fighter like Floyd, his defence is impregnable, he doesn't get hit.

"With a fighter like that you can't say it only takes one punch because he doesn't get hit.

"If he goes in there and respects Floyd, thinking 'I'm in the ring with this undefeated, pound-for-pound king', then he'll get wiped out.

"If he goes in there thinking 'I'm Conor McGregor, I don't care who this guy is, I'm going to do what I do and I'm going to beat him', that's the only chance he has - if he goes in there and truly believes he can do it."