Eighteen years have passed since Calzaghe left any ring as loser.
Calzaghe has reserved his best for the biggest bouts
A Romanian amateur, Adrian Opreda, out-pointed the 17-year-old Welshman at the European Junior Championships.
He says that he cried like a baby in the dressing room afterwards, but vowed he'd never be a loser again.
So far he's stuck firmly to that promise.
Calzaghe fights at his best when his back is against the wall, when journalists start to get twitchy about whether this fight will be the first defeat in almost two decades.
The problem is that Joe is an extraordinary sportsman.
He knows that he can beat the likes of Peter Manfredo, Mger Mkrthchian and Branko Sobot without bringing his "A-Game".
You don't see the best of Calzaghe in those fights because he's not 100% motivated for them.
It's the same attitude which meant his meetings with David Starie, Kabary Salem and Sakio Bika took the full 12 rounds.
It is names and performances like these which lure Bernard Hopkins and the American media into a false sense of security.
"Who's he fought? Where are the future Hall of Famers on his CV?" asked the Philadelphian last week. Fair point.
Put the records of the two men next to one another and look simply at the names and you'll convince yourself that "The Executioner" is the only victor come 19 April.
Eubank, Woodhall, Mitchell, Lacy and Kessler have all been dealt with brilliantly by Calzaghe
Oscar De La Hoya, Winky Wright and Tito Trinidad have all succumbed to Hopkins. Impressive; until you look further.
The wins over De La Hoya and Trinidad were at middleweight.
Both men were moving up through the weights and weren't in their best division.
De La Hoya was a blown-up super-featherweight, Trinidad a natural welterweight.
Winky Wright was beaten in a light-heavyweight snooze-fest; Wright is a light-middleweight.
Calzaghe's best comes when he's up against fighters he knows have a good chance of adding their name next to Opreda's as men who've come out on top against Wales' finest.
Eubank, Woodhall, Mitchell, Lacy and Kessler have all been dealt with brilliantly by Calzaghe.
That's when you see the legendary hand speed, the underrated defence and boxing mind of Britain's greatest modern fighter.
Hopkins is a major threat and Calzaghe knows it.
Hopkins will try anything to come out on top
He also knows that he'll have to "go to the mattresses", as Sonito Corleone put it in the Godfather, if he's to win.
Hopkins will try ANYTHING to come out on top. Every punch he throws brings with it the forearm, the elbow and sometimes even a cheeky head butt.
He also knows that Vegas is new to him. Being in a training camp away from the "comforts" of the pebble-dashed, ice-cold shack that he calls home will show us whether he can travel and still put in a winning performance.
It's all new territory. A new country to convince that he is the best. A new weight class to attempt to dominate. A new, cunning and tricky opponent.
But I wouldn't bet against the same old outcome, with Bernard Hopkins' name added to the 44 other pro fighters who've been beaten by Joe Calzaghe, rather than joining Adrian Opreda in a very exclusive club.