Ireland kept its Six Nations title hopes on track with a 19-13 win over England at Lansdowne Road on Sunday.
A try by captain Brian O'Driscoll and 14 points off the boot of Ronan O'Gara -- surpassing 500 points in international rugby -- lifted Ireland atop the standings with Wales, the only unbeaten teams with two rounds remaining.
England, which had two tries disallowed against Ireland, has lost the opening three matches in the tournament for the first time since 1987.
"It's always a special win for Ireland to beat England but we made hard work of it in the end," said O'Gara, celebrating his 50th cap. "We never take a win over England lightly."
Ireland, chasing its first championship in 20 years, faces Wales in the final round on March 19. Before then, the Irish host defending champion France on March 12, and Wales will be in Scotland the next day.
O'Gara put Ireland ahead with a fourth-minute drop goal but, three minutes later, England No. 8 Martin Corry picked the ball up from a ruck and ran unchallenged over the Ireland line. It was converted by flyhalf Charlie Hodgson, whose kicking was under scrutiny after he missed three penalties and a drop goal in the one-point loss to France two weeks ago.
O'Gara scored two penalties to edge Ireland ahead 9-7. Hodgson slotted a second successful penalty from halfway, before an O'Gara drop goal went in off the post.
England then had a try by winger Mark Cueto disallowed for offside just before halftime.
Hodgson kicked England 13-12 ahead with a drop goal after 57 minutes, but O'Driscoll touched down to give Ireland some breathing room. O'Gara converted for a 19-13 lead but missed a drop goal under pressure from Lewis Moody.
* Ireland 19: Brian O'Driscoll try; Ronan O'Gara 2 penalties, 2 drop goals, conversion
* England 13: Martin Corry try; Charlie Hodgson conversion, penalty, drop goal
* Halftime: 12-10
England was given a penalty in front of the posts but kicked to the corner to go for the try rather than three points. Josh Lewsey went over the line with the ball, but the try wasn't given because he didn't ground it.
England coach Andy Robinson was angry at his side's two disallowed tries, saying video replays should have been used by South African referee Jonathan Kaplan.
"It is there, and it should be used," Robinson said. "I am still trying to work out the Cueto try. I have looked at both, and they both looked like tries.
"We are very disappointed, and this will hurt, there is no doubt about that. We are upset now, but the referee is in charge and he has called it his way, and we have got to be able to cope with that."
England has lost nine of its last 12 tests, and has been narrowly edged 11-9 by Wales, and 18-17 by France.
"We have done everything but win a game of rugby, but Ireland are a good side," Robinson said. "They defended magnificently and they've got every chance of winning this Six Nations.
"This was our best performance in the championship this season to date, and we just need that little bit of luck. If a couple of decisions had gone our way, it could have been a famous victory for us."