They just cannot stop winning, those Welsh, which is something no one expected us to be saying a few weeks ago. Nor will anyone in Wales be getting too carried away, even if their chances of winning the Six Nations remain alive. Because not only was this a wild game without structure, it was a game won by a suitably lawless piece of opportunism.

Jonathan Sexton had just come on for Ronan O'Gara, around 10 minutes into the second half, when he skewed a kick straight into touch. The ball went beyond the advertising hoardings and into the hands of the crowd. Meanwhile, Matthew Rees quietly collected another ball from an official and prepared to take the lineout, just inside the Irish half.

Mike Phillips saw a chance, though, and, starting his run, called to Rees, who threw a quick lineout to him. Suddenly, Phillips was galloping clear and, fending off the despairing tackle of Tommy Bowe, he was over in the corner. The referee consulted with Peter Allan, the nearest touch-judge, who had nothing to report. He surely would have done if he had seen that Rees had taken the quick throw-in with a different ball to the one that was kicked out. That is not allowed, but on such lucky breaks can seasons turn round.

Wales now have three wins on the trot and if they win in France next Saturday they will rue for sure their inability to beat England at home on the opening weekend. Here the main improvement was at the lineout, which was solid, and the aggression of their tackling. There were glimpses of flair, but the Irish line remained safe but for Phillips's cheeky breach of it. They did more than enough to ruffle an Ireland side who have never looked happy this season, but this was a game that could have gone either way. Neither will be terribly proud of it.

The match was dominated by Wales for the most part, which meant it was a game played without much in the way of structure. Ireland did look the more deadly when they were able to string things together. There was something coiled about them; it was just that they were not given much chance to unwind into their game.

Wales were feisty in contact, Sam Warburton furthering his burgeoning reputation, and they were not afraid to look for contact when in possession. But they were not quite threatening Ireland's line, other than when Bradley Davies and Warburton drove off the side of a ruck. Rory Best conceded a penalty for going off his feet, although it might just as easily have gone against Warburton for holding on, and James Hook kicked his second penalty.

That brought Wales to within a point of Ireland with half an hour gone. They had been chasing the game courtesy of Ireland's lightening start. First of all, quick as a flash, Eoin Reddan was off, not even seeing out the first minute – victim of a Lee Byrne punt into the face. So Peter Stringer came on to resume that partnership of ages with O'Gara. The first thing he did was to set in motion a back division that looked imperious for a couple of minutes, crowned with a record-equalling 24th championship try for Brian O'Driscoll, taking a pass from Bowe, whose half-break past his Ospreys team-mate Alun Wyn Jones presented him with a clear run to the line.

But that was the last we saw of Irish coherence for a while, testament as much as anything to the aggressive defence of the Welsh. One hit cost Wales their umpteenth prop of the season when Craig Mitchell, whose first scrum of the afternoon had looked promising for Wales, popped his shoulder in a hit on Cian Healy. The recently recovered Adam Jones may yet see action in this championship.

Neither side was putting together much of a kicking game, which contributed to the general lawlessness of the occasion. Not that there was much in the way of criminality – the two most undisciplined teams of the championship did not concede a penalty until the 16th minute. Hook missed that one, hitting a post, but his first successful penalty was landed soon afterwards.

O'Gara responded with a penalty from one of those dodgy penalties at a collapsed scrum to open up a four-point lead that stood at the break after Leigh Halfpenny and O'Gara exchanged a penalty each in the three minutes leading up to half-time.

The wildness of the game continued after the break and never more so than when Rees and Phillips combined to break things open. Ireland seemed to respond immediately, with Keith Earls streaking through the Welsh defence out wide, and a phase or two later Luke Fitzgerald was scything over the line off Donncha O'Callaghan's pass. The pass, though, was called forward. It was mighty close. On such little things ...

Nevertheless, the game was called back for an Ireland penalty – an easy one to get Sexton back into the swing. He lined up the simple shot, slightly to the right of the posts, that would have tied things up at 16-16. He missed it. And now Ireland really did look lost.

Wales played with the greater vim for the next 25 minutes, harvesting another Hook penalty to take them six points clear with 10 minutes to go. Inevitably, though, Ireland were not done. They tried a few lineout and drives, then, in the last play of the game, Paddy Wallace, ignoring the man outside him, seemed to have cut through. He was stopped just short, and when Healy was hit by Jamie Roberts in a mighty tackle that forced the umpteenth spill of the game, Shane Williams hoofed the ball into the crowd this time, and – with the roof off – the Millennium Stadium let off its loudest roar of the season so far. You take what you can get.