There’s a saying in boxing that it’s easier to win a world title than to defend it successfully — if the defence is against a legitimate, high-ranking opponent. That’s because a challenger gets himself psychologically and physically ready for the greatest fight of his life, reaches the pinnacle and then has to buckle down and do it all again.

Ireland’s Bernard Dunne finds himself in this position on Saturday when he defends his WBA 122-pound title against the Thai, Poonsawat, in Dublin.

When Dunne won the title he surprised many people by knocking out Ricardo Cordoba in an epic fight in Dublin six months ago.

Down twice in the fifth round and behind in the scoring, Dunne hurt a tiring Cordoba in the 11th and stormed to victory by dropping the Panamanian southpaw three times. It was stirring stuff.

Dunne, 29, fought above anything he had ever shown before. He looked bigger, stronger and was punching harder than in any of his past fights. What particularly impressed me was that, after the dreadful fifth round, he rallied to win the sixth on two judges’ cards. After coming close to losing, he dragged himself right back into the fight in the next round. It takes a big-hearted, special fighter to make that sort of fight-back. Dunne’s determination and desire for victory that night were astonishing.

I think that the crowd helped Dunne immensely. The support he received was such that he could tap into it and draw strength from it. It was as if every soul in the crowd was willing Dunne to victory.

Dunne will have that passionate backing from the Irish fans when he takes to the ring against Poonsawat, and although the Thai has boxed in Germany he will never have experienced anything like the tension-crackling atmosphere that he will encounter at The O2 in Dublin.

Will Poonsawat be mentally strong enough, I wonder, to shut out the crowd’s clamour and maintain the discipline and focus that he will need if he is to win? Can Dunne, after the spectacular showing against Cordoba, do it again? These are the two biggest questions I have as the fight draws near.

Poonsawat, 28, is Dunne’s mandatory challenger, so this is a fight that had to be made — I am sure that Dunne’s promoter, Brian Peters, would have preferred a less demanding first defence.

The Thai holds a win over Cordoba, by decision, and he stopped former champion Somsak with a left hook to the body in the 11th round of a fight that Poonsawat dominated. With just one loss in 39 fights, Poonsawat has the credentials that make him a worthy challenger.

Thai boxers normally do not travel well, though, and Poonsawat was beaten on a unanimous decision by Wladimir Sidorenko in Germany although the scoring was all over the place with a Swedish judge giving the Ukrainian fighter every round while a Japanese judge had it close, 115-113.

Looking back at my notes on that fight, I find that I had Sidorenko winning by 115-113 with the note that the Ukrainian boxer looked the worse for wear at the end.

After eight rounds this looked, to me, like anyone’s fight, but Sidorenko, normally a pressure fighter, won by shuffling the deck on Poonsawat and going to a moving, boxing style in the last four rounds. Poonsawat kept pressing forwards but he was made to miss and kept running into counters and he was outscored in the home straight.

The key to Dunne winning, I think, is to keep on the move, using the jab, getting off with combinations, and not allowing Poonsawat to get close enough to bang to the body.

Dunne has significant height and reach advantages, and he showed how well he can box in his comfortable points win over Esham Pickering, a capable European-level fighter at the time. Pickering could hardly lay a glove on Dunne, although one judge had the fight surprisingly close.

There is probably always going to be a doubt about Dunne’s chin after his 86-second loss to Kiko Martinez, but he was simply caught cold by the Spanish fighter and I tend to dismiss this result as something of an accident.

Dunne looks a much stronger fighter these days after bringing strength and conditioning coach Mike McGurn on board, and he has had a three-month training camp for this fight.

Despite the two knockdowns, I thought Dunne showed a good chin against Cordoba — once he had survived the shaky fifth round he seemed to be taking Cordoba’s punches without much of a problem for the remainder of the fight. So, I certainly don’t see Poonsawat blowing Dunne out: I would be very surprised indeed if this happened.

I am always impressed when a fighter’s camp goes to the added expense of bringing in a top-quality sparring partner from overseas, and Dunne has been sparring with Montreal’s Olivier Lontchi, who showed his toughness in lasting nine rounds against the powerful Juan Manuel Lopez.

The mood in Dunne’s camp is upbeat, with Dunne’s trainer, Harry Hawkins, telling the Irish media: “Bernard is hungrier than ever right now and that’s been reflected in his training for this fight. It’s one thing to win a world title but it’s another thing to defend it and establish yourself as one of the very best, and that’s what Bernard wants to do. He wants to prove he’s the best, and beating this guy will make another big statement.”

Dunne is the favourite, and if he gets off to a fast, positive start, piling up the points, he might well be able to carry the momentum through to the finishing post. The crowd will be roaring every time Dunne lands a punch and jeering when Poonsawat is made to miss — and I can see the Thai missing a lot in this fight.

Poonsawat does look strong, tough and tenacious, however. I do not regard him as a big puncher as such, but he can hit hard with the left hook and it seems to me that he has good hand speed and punch variety.

What Poonsawat has to do is to land something significant early in the fight that will give him encouragement. Even if he cannot drop Dunne, if he can shake or stagger him it will give Poonsawat the knowledge that if he patiently keeps the pressure on his taller, faster opponent his chance will come. If Poonsawat falls behind early, though, starts eating jabs and becomes frustrated, winging and missing and generally not having much success, the fight could rapidly reach the point where he will need a knockout to win — and when a fighter has to get a knockout it is very hard to accomplish the objective.

There is, though, a relentless quality in Poonsawat’s fighting that impresses me. I think he is the type who will keep up a steady pace, round after round, and if he can start to close the gap and hit the target there is a chance that he can slow down Dunne and start to come on strongly in the later rounds.

A Dublin publicity poster shows Dunne’s image with the word “Believe” in capital letters underneath. The vast majority of the crowd will be believers now if they weren’t before — but will they again go home happy?

I have wrestled with a prediction and it would not surprise me to see Dunne boxing his way to victory, but Poonsawat, I think, might be a little too much for him. Cordoba had the fight won, but he exhausted himself trying to get a stoppage, and as he faded so his punch-resistance ebbed. I believe that Poonsawat is the type who will be able to fight strongly from first bell to last. In a toss-of-the-coin fight, I’m swaying towards Poonsawat, on points.