Jonathan Davies: Iestyn a test for the very best of Brian

While there is no doubt in my mind that this afternoon's match in Dublin will be won and lost in the front five, it is another fascinating Six Nations occasion when the role of the midfield player will come under intense scrutiny. As with England and their selection of Jason Robinson, Ireland have tinkered with their back line in search of the best combination to open up defences. Wales will believe that, as we all saw against Scotland, they have the ability to exploit any weakness in the system.

So here we find the Irish fielding the man I still regard as the world's best outside- centre, Brian O'Driscoll, at inside-centre, while Gordon D'Arcy keeps the No 13 jersey he wore against France. Maybe Eddie O'Sullivan, Ireland's coach, will look to mix things up in midfield more than he is letting on.

One thing I am confident in predicting is that Wales will not capitulate the way they did in conceding 50-odd points in this same fixture two years ago. Iestyn Harris had a shocker that day; they all did. This time Iestyn and the rest of the team have that vital ingredient, confidence, gained from their World Cup performances and their comfortable win over Scotland.

At inside-centre for Wales, Iestyn will be out to pick holes in the O'Driscoll-D'Arcy pairing, which is absolutely untested in this formation. Harris made the first try against the Scots with a break typical of his talent, and team-mates are beginning to read him and his moves. But this is a fresh test, because Scotland gave Iestyn a cushy ride.

The glaringly obvious question is whether Wales were particularly good last week, or did the Scots contribute to their own downfall? Certainly we saw the worst defensive performance in a Six Nations match for a long time, but I was delighted with the way Wales took advantage. The forwards gave the backs the platform to play with a lot of width. This hasn't happened by accident for Steve Hansen, as some people have suggested. He has put a lot of work into it. Wales lost confidence in the transition from Graham Henry to Hansen. They have perked up now, and praise must also go to the fitness coach, Andrew Hore - they are looking fitter and stronger.

Choosing when to run or kick will be crucial today. The crowd are on top of you at Lansdowne Road, it gets windy even on a sunny day, and there always seem to be 17 or 18 green jerseys on the field, such is the pace of the game. Every slight decision will be magnified in importance. Harris, Steve Jones and Gareth Cooper must shoulder plenty of responsibility. If they heap too much pressure on the back three, Wales could find themselves isolated behind the gain line with half of Ireland on top of them. Gareth Thomas is fine under the high ball, so I would hazard a guess that the garryowen will be a treat the Irish reserve for Shane Williams and Rhys Williams on the wings.

You cannot play the Welsh way if you are on the back foot, which returns us to the forwards. Hansen has changed a winning team, and if he is picking horses for courses, I'd back him all the way. Duncan Jones must be upset at being dropped from the front row, but I would think the recall of Iestyn Thomas along with Robin McBryde is to secure the scrum. Ireland will be a lot more physical than Scotland.

Colin Charvis is out injured, and that will be a blow to Wales, with Ireland fancying themselves in the loose. Robert Sidoli and Paul O'Connell are two of the best young locks around, and theirs is just one of many interesting head-to-heads. The big difference from 2002, and the horrendous beating that heralded the end of Henry, is that I fancy Wales to win, if the forwards go well.

And that will do for me, for now. It is enough to say that Wales have a chance of victory on what, for all its unique and testing atmosphere, used to be one of our happier hunting grounds. There is no need to get carried away, and definitely no need to think about a first Triple Crown since 1988.

Wales need only to concentrate on finding the balance between panache and practicality. Ireland are looking to bounce back themselves. Something has to give. It could be a classic.