Leigh Halfpenny's last-minute penalty gave Wales a 23-21 win over Ireland in an enthralling Six Nations rugby battle as the hosts failed to avenge last year's World Cup quarter-final defeat.
Wales, missing several first-team players, were well on top in the early exchanges of their championship opener.
Ryan Jones was denied a try by the video referee before Jonathan Davies was adjudged to have got the ball down after a superb offload by Rhys Priestland, who struck the post with the conversion and a penalty.
Ireland, without the injured Brian O'Driscoll, hit back with a Rory Best try after a great Tommy Bowe dummy just before halftime only for Davies to grab his second touchdown after the break as Wales led.
Bowe put the Irish clear with his own try on 68 minutes but George North went over for Wales late on to move within a point.
Stephen Ferris then joined Bradley Davies in the sin bin as both were punished for dangerous tackles and Halfpenny slotted the penalty through the posts for a dramatic victory.
England beat Scotland and France overcame Italy on Sunday's opening day of matches.
Ireland travel to France next weekend while Wales host Scotland on Monday.