Ireland defeated Wales 17-15 in a game of dramatic and escalating tension at the Millennium Stadium to win their first Six Nations grand slam since 1948.
Out-half Ronan O'Gara dropped the winning goal three minutes from time after captain Brian O'Driscoll and right wing Tommy Bowe had scored tries in quick succession to put Ireland 14-6 ahead early in the second half.
Welsh fly-half Stephen Jones, who kicked the only points of the first half, kept the defending champions in contention with two nerveless penalties and Gavin Henson failed with an ambitious attempt from halfway.
Five minutes from time, Jones brought the home fans in the packed stadium to their feet with a dropped goal which soared between the posts to give Wales a one-point margin and take his tally to 15.
But Ireland were not to be denied. They surged back into the Welsh half, set up the ruck and O'Gara, gesturing frantically for the ball, dropped the most important goal of his illustrious career.
After the week-long build-up, both teams were understandably nervous on a warm, spring afternoon and the first half was riddled with errors, turnovers and a host of indifferent kicking from hand.
Jones finally broke the deadlock with a penalty in the 32nd minute when replacement flanker Denis Leamy was penalised inside the 22 for not rolling away from the ball.
The Welsh number 10 was successful with a second long-range penalty two minutes from halftime after wing Luke Fitzgerald got in the way of a defender and was penalised for shepherding.
Ireland were a different side after the break. Bowe shot down the right wing in the opening minute, the ball went left and from the lineout Ireland launched a series of pick-and-drives.
The unstoppable O'Driscoll finally barged over for his fourth try of the tournament, awarded after a long wait while the television match official examined the video.
Two minutes later Bowe, who had an outstanding game, raced on to a deft O'Gara kick to seize the ball and race between the posts to score.
Although Wales had their chances, notably when scrum-half Mike Phillips skipped through a series of tackles before being dragged down near the line and Jones failed with a penalty kick in the last minute, the force was with Ireland.