Kell Brook found out just how tough the boxing business can be when he fought Carson Jones a year ago - and when the two meet again on Saturday night we'll see whether the Sheffield fighter has learnt from that experience.
The man they call 'Special K' was beating all of his opponents comfortably before he met Jones; boxing was a wonderful job for him because it just came so easily. But his bout with the American almost turned into a nightmare.
Brook dominated with his skills for the first six or seven rounds but then he seemed to get a little bit tired and let Jones come back into the match. Jones isn't particularly gifted as a boxer but he's tough, he can take punches and was in great shape that night - and he just kept on coming at Brook.
Kell had to dig in and show real character and to his credit he did that; I remember the 11th round, when it looked like Brook had nothing left but needed to win another round and he came out and showed his heart.
Against Jones Brook suddenly found out how hard boxing can be.
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Kell Brook v Carson Jones & Luke Campbell v Andy Harris
8pm, Sat, Sky Sports 1 HD
You'd think that fight will have given Brook confidence and that he'd have grown from that - but it might have had the opposite effect as well. He suddenly found out how hard boxing can be.
Since that fight last July, Brook has boxed once, beating Argentina's Hector Saldivia inside three rounds, but had his world title fight with IBF champ Devon Alexander called off three times and, to be honest, his career has stalled.
His promoters should be banging the drum and saying how desperate Brook is to get the Alexander fight on - but I don't hear any of that.
The Alexander call-offs will have been frustrating for Brook and now he's going over old ground.
Brook-Jones is a good match-up, an interesting one and a fight which the promoters knew would sell tickets - but Kell knows in his heart of hearts his next fight should have been to see if he'd be world champion and realise his dream.
Kell's naturally talented so I don't think ring rust will be a problem - as long as his training and sparring has been right - but it is never good to be out of action for so long and he could have problems mentally. He's at a tough stage in his career and it's a stage he needs to get through.
The rematch with Jones will give us a gauge of whether Kell is a better boxer now, whether he's in better condition than he was 12 months ago and whether he can maintain what he did for six or seven rounds last time for the full dozen.
If it turns into another war and Kell has to dig deep again then you'd have doubts about him when he eventually faces Alexander but I fancy him to win on points, with a bit more conviction than in 2012.
Brook is a different class to Jones and the Oklahoman was very disappointing last time he fought in Britain, when he drew with Dean Byrne in December. Okay, he was expecting to fight Lee Purdy and ended up against a journeyman, but he was atrocious, terrible.
All Jones has is his toughness and if Kell is in his best shape, you have to expect a resounding points victory.
Saturday night's event is called 'Homecoming' and Hull-born Luke Campbell is sure to get a fantastic reception from the fans at Craven Park; the 25-year-old is making his pro debut and I have to say he's a terrific prospect.
It will be difficult for him because, like Amir Khan, he's straight under the spotlight and his team will have to take their time with him but Campbell had an outstanding amateur career and he's a great talent.
He has come in a bit heavier than he did as an amateur and we'll see how he looks at bantamweight and what division he'll box in as his career progresses. But it is great Sky Sports is there at the start and it will be interesting to see how far he can go.
The pro game is a completely different sport to amateur boxing and we have seen plenty of fighters fail to make the transition. You need stamina, strength and a real will to win to succeed as a professional, whereas you'll get by on skill alone in the amateurs.
However, there's plenty of time for Luke and his team to worry about that.
His first few fights won't tell us too much but when they start stepping up the quality we'll tell how good he's going to be - but I think he's going to be really good.