George North silenced his critics with a brace of tries that saw Wales run out 22-9 winners over Ireland in Cardiff on Friday to end the visitors' hopes of a tilt at the Six Nations title.
The result means England will be crowned Six Nations champions should they beat Scotland on Saturday.
North scored a try in each half and Jamie Roberts a late five-pointer, Leigh Halfpenny kicking two conversions and a penalty. Ireland, who had Jonny Sexton sin-binned, had just three penalties to show for their efforts through the Leinster fly-half (2) and Paddy Jackson.
"We knew we were one performance away from winning a game, they have been down to fine margins every week," man-of-the-match and scrum-half Rhys Webb told BBC.
"We showed glimpses of what we can do and there is more to come from us. You don't become a bad team overnight."
Wales captain Alun Wyn Jones added: "We owed that to the Welsh people and to ourselves. We haven't done ourselves justice in the last two games."
Irish skipper Rory Best admitted that his team, who bounced back from an opening defeat by Scotland with wins over Italy and France, were "very disappointed".
"We came here hoping and expecting to win and keep everything alive. Credit to Wales but we are frustrated with the errors we made."
It was a brutal match, the ferocity of some of the early bone-jarring hits reverberating around a packed, expectant Principality Stadium in full song: Ireland made 81 tackles in the first half alone.
Recent encounters between the Celtic cousins have been closely-fought affairs, and this attritional ding-dong was no different, although the winning margin was Wales' best since 1983.
Ireland dominated a frantic opening period, monopolising both possession and territory. The pressure eventually paid off after Webb was penalised for a high tackle, Sexton making no mistake with the long-range kick at the posts.
Wales, who opened their Six Nations campaign with victory over Italy before losing to England the Scots, came battering back, but the Irish defence held firm.
Breaks from South African-born flanker CJ Stander and winger Simon Zebo kept Wales pinned back, but the visitors suffered a blow when a groggy Sexton, who caught a Jonathan Davies knee to his head, was replaced by Paddy Jackson in the 19th minute.
No sooner had the replacement come on then Wales sprang from a line-out.
Ireland coach Joe Schmidt had predicted before the match that players can bounce back from a poor display with a much-improved one, and so it proved to be for North, heavily criticised in Wales' capitulation to Scotland.
Webb broke into midfield and found Halfpenny with a long pass, the Toulon full-back fed North who stepped inside Keith Earls and rode Zebo's tackle for a fine try.
Halfpenny missed the conversion and Jackson restored Ireland's lead with a penalty.
- Wales in ascendancy -
Wales ended an entertaining half in the ascendancy, however, a Webb chip to the corner gathered by Liam Williams who fed inside only for Davies to be held up.
English referee Wayne Barnes had no choice but to yellow card Sexton for killing the ball on the line, Halfpenny making no mistake with the resulting penalty.
Wales made their numerical supremacy pay immediately into the second period, Halfpenny doing well to follow up a Webb chip and bundle the covering, obviously injured Connor Murray into touch.
Alun Wyn Jones rose to pluck the ball in the resulting line-out, the maul trundled forwards and Webb found North unmarked on his wing for a simple try, his 30th on the international stage. Halfpenny knocking over the extras.
The returned Sexton orchestrated an Irish fightback, Wales withstanding a remarkable 26-phase of attack before Dan Biggar was harshly penalised for a high tackle, Sexton pulling back three points.
Biggar saw a drop-goal go off the post as a raft of replacements came on in what was turning into a war of attrition.
And then Robbie Henshaw arguably cost Ireland a pushover try when he joined a driving maul illegally.
Sexton conjured up a couple of pinpoint cross-kicks that threatened the Welsh line late on, but the home side had the last word when Roberts barrelled over from close quarters, Halfpenny booting the conversion to leave coach Rob Howley and his coaching staff breathing a massive sigh of relief after two weeks of intense scrutiny over their selection policy.