Scott Williams' second-half try was enough for Wales to end Ireland's Grand Slam hopes 23-16 in a titanic tussle in Cardiff.
After racing into a 12-0 lead, Wales spent large periods of the second half camped in their own 22, but showed that for all their tactical nous, Ireland are still struggling a little on the try-scoring front.
A penalty try ten minutes from time did give Ireland hope at the Millennium Stadium, but Leigh Halfpenny responded with a penalty that appeared to have sealed the win, and despite a final effort from the Irish, Wales hung on.
Wales racked up an unbelievable 289 tackles, as Ireland lay siege to their line in the second half, but with the exception of one maul, the Irish couldn't find a way through.
Despite yellow cards for both Sam Warburton and Jonathan Davies, Warren Gatland's side held on for the win, and are now right back in contention for the Six Nations title before next week's trip to Italy.
Wales took the lead within two minutes when Ireland ventured offside in the first passage of play. Warren Gatland's men were dominant early, and after a long period in the Irish 22, Peter O'Mahony cynically killed the ball in a ruck, conceding a penalty, which Halfpenny converted to make it 6-0.
In the build-up to that second penalty, Leigh Halfpenny had brilliantly claimed a high ball out of the hands of Conor Murray, while Davies had then handed off Johnny Sexton on a powerful charge.
It was all Wales, and on Ireland first extended period of possession, Gethin Jenkins got in well at a ruck to earn a penalty, which Halfpenny converted from halfway to make it 9-0 after just ten minutes.
Ireland seemed rattled, and that was evident when Sexton put the restart out on the full. From the resulting scrum, Wales were dealt a big blow though, with Samson Lee injured and receiving oxygen before going off. The game had carried on and after Jack McGrath slowed the ball down in a ruck to allow Halfpenny to make it 12-0.
Finally Ireland got themselves into the game when George North failed to release the tackled player in a ruck, and while Sexton was off-target with his first penalty attempt, he made up for it a minute later when Scott Baldwin caught Tommy Bowe high round the neck.
Ireland were finally getting themselves into the game, and after another long period of possession, it was the Welsh who failed to roll away on a number of occasions, with Dan Biggar the man finally penalised.
The visitors turned down the three points, but Rory Best's lineout was stolen by Warburton, who was then taken out in the air by Devin Toner as the chance went begging.
Wales earned another penalty a minute later when the Irish collapsed a promising maul, but they saw a chance of their own disappear when they knocked on a lineout on the visiting 22, with Aaron Jarvis struggling in the next scrum and conceding a penalty.
Just before the half-hour Wales lost Warburton to a yellow card. The Welsh skipper tried to contest a ball at the breakdown but referee Wayne Barnes deemed that he hadn't released the tackler. It was probably the right call, although it seemed a little harsh, with the visitors having been heavily penalised in the opening quarter without conceding a card.
Sexton made no mistake with the resulting penalty, as Ireland looked to be in the ascendancy, but Wales responded and set up Biggar in position to knock over a drop goal and push the lead back to nine points.
It didn't last long though, with Ireland again looking dangerous, Paul O'Connell – on his 100th Ireland appearance – made a half-break and a couple of phases later was tackled without the ball, allowing Sexton to add three more points.
In the end the ten minutes at 14 cost Wales just three points, and Warburton returned just before half-time as Warren Gatland's side went in 15-9 ahead.
The second half was even more frenetic with the first, beginning with an endless period of Irish pressure. Time and again they looked certain to score, but the Welsh defence held strong, thumping back the visiting forwards.
After more than 30 phases, Wales were penalised, but having kicked to the corner, Ireland eventually lost the ball after another spell on the Welsh line.
Having spent a good ten minutes defending, Wales came back, and looked set to score the first try of the game when Davies went clean through but the support wasn't there. Still Wales kept the ball and twice seemed to have overlaps but eventually the chance went begging when Biggar overthrew Halfpenny out wide.
Gatland chose to introduce Scott Williams at that moment and after the home side had stolen yet another lineout, the Scarlets centre spotted a gap in midfield and sprinted over for the first try. Halfpenny was off-target with the conversion but Wales led 20-9, and it was a long way back for the visitors.
Ireland weren't about to give up though, and they set up camp again on the Welsh line and should have scored. With a massive overlap, they kept going through the forwards, with Cian Healy eventually knocking on.
By that point Wales had already racked up more than 200 tackles, and it was beginning to show. When Dan Lydiate was penalised in a ruck, Ireland kicked to the corner.
Sean Cronin had more success than Best in the lineout, and after a well-structured maul, Ireland got a penalty try, with the Welsh dropping it just short of the line. Sexton converted and it was back to 20-16 with ten minutes remaining.
Wales came back, and earned a penalty that Halfpenny converted, but Ireland refused to bow down.
They got back into Welsh territory, and with three minutes remaining Davies was sin-binned for an intentional knock-on. Ian Madigan kicked for the corner, but after a first lineout had been stolen, Wales then slowed a final rolling maul, with Luke Charteris fighting through to the ball to cap a splendid afternoon for the giant lock.
Wales remain outsiders to win the title, they have 21 points to make up on Ireland on the final weekend, unless the Scots can do them a favour. Still, they'll take it after the disappointment of that opening defeat to England.
As for Ireland, O'Connell special day was spoilt, while their run of ten straight wins comes to an end. They dominated possession and territory, but will need to find a little more penetration against the best defensive sides. Their much-lauded half-back partnership was also off-colour.
Man of the match: Sam Warburton was given the official nod, and certainly had an outstanding game. We're going to go with Luke Charteris though, as he finished with 37 tackles, as well constantly breaking up the Irish maul.
Moment of the match: It has to be the endless period of Irish possession early in the second half. It seemed like a try was inevitable but Wales somehow held out before going up the pitch and scoring themselves.
Villain of the match: Nothing nasty to report.
Try: S Williams
Pens: Halfpenny 5
Drop Goal: Biggar
Yellow Cards: Warburton, Davies
Pens: Sexton 3
Wales: 15 Leigh Halfpenny, 14 George North, 13 Jonathan Davies, 12 Jamie Roberts, 11 Liam Williams, 10 Dan Biggar, 9 Rhys Webb, 8 Taulupe Faletau, 7 Sam Warburton (c), 6 Dan Lydiate, 5 Alun-Wyn Jones, 4 Luke Charteris, 3 Samson Lee, 2 Scott Baldwin, 1 Gethin Jenkins.
Replacements: 16 Richard Hibbard, 17 Rob Evans, 18 Aaron Jarvis, 19 Jake Ball, 20 Justin Tipuric, 21 Mike Phillips, 22 Rhys Priestland, 23 Scott Williams.
Ireland: 15 Rob Kearney, 14 Tommy Bowe, 13 Jared Payne, 12 Robbie Henshaw, 11 Simon Zebo, 10 Jonathan Sexton, 9 Conor Murray, 8 Jamie Heaslip, 7 Sean O'Brien, 6 Peter O'Mahony, 5 Paul O'Connell (c), 4 Devin Toner, 3 Mike Ross, 2 Rory Best, 1 Jack McGrath.
Replacements: 16 Sean Cronin, 17 Cian Healy, 18 Martin Moore, 19 Iain Henderson, 20 Jordi Murphy, 21 Eoin Reddan, 22 Ian Madigan, 23 Felix Jones.
Venue: Millennium Stadium, Cardiff
Referee: Wayne Barnes (England)
Assistant Referees: Pascal Gaüzère (France), Federico Anselmi (Argentina)
TMO: Graham Hughes