Owen Farrell held his nerve as England beat Ireland 12-6 at a rain-soaked Lansdowne Road on Sunday and so became the only side in this season's Six Nations capable of winning the Grand Slam.
In an attritional, forward-dominated contest, the 21-year-old fly-half scored all his side's points by landing four penalties as England ended a decade of Championship misery in Dublin with a first Six Nations win in the Irish capital since 2003 - the last year they won the Grand Slam and, later, the World Cup.
Ireland, who had Slam hopes of their own after beating defending champions Wales in Dublin last week, saw replacement fly-half Ronan O'Gara tie the match at 6-6 with two second half penalties after England led 6-0 at the break.
However, with 10 minutes left, O'Gara missed a penalty and that meant Ireland now needed a converted try to win the match.
But with England captain and openside flanker Chris Robshaw producing a man-of-the match display at the breakdown, it was the visitors who triumphed.
Defeat ensured there was no double celebration for Brian O'Driscoll after the Ireland great's wife, Amy, gave birth to the couple's first child, a daughter, earlier on Sunday.
England coach Stuart Lancaster said that the tough conditions had made it a grim battle between the two sides.
"I think we had a good first half, but at the start of the second we had a couple of turnovers that put us under pressure," he told the BBC.
"I think we grew in stature towards the end of the game and deserved our win. We hadn't won here for a long time and we went and did it. We will take it."
Meanwhile Robshaw paid tribute to Farrell by saying: "He's got a great repertoire of skills, but he's got a great team around him who keep pushing him to get better. We're not going to get carried away."
And Farrell, who landed four of his six goal-kicks, said: "If you practise enough it's only another kick. I kick thousands of them."
Ireland captain Jamie Heaslip had no complaints about the result.
"They (England) played the conditions very well, smothered us when we had ball and made our lives very hard," said the No 8.
Farrell gave England an early lead with a second minute penalty.
Tempers flared in the 14th minute when Ireland prop Cian Healy's use of the boot on England's Dan Cole at a ruck sparked a mass brawl in a match featuring several candidates for this year's British and Irish Lions tour of Australia.
In such a tight contest, discipline was especially important, and Farrell punished Ireland for coming around the wrong side of a ruck with a superb penalty from nearly 50 metres to make it 6-0 to England in the 28th minute.
Ireland lost fly-half Jonathan Sexton with a hamstring pull just after the half-hour mark.