Ireland kept their Grand Slam dream alive - and remained on course for a potential winner-takes-all RBS 6 Nations Championship showdown with Wales - by inflicting further misery on Andy Robinson's England.
England slumped to their fourth successive championship defeat - their worst sequence for 18 years - even though they produced a much better display than against France two weeks ago.
The world champions, and regular wooden spoon contenders Italy, are now the only teams without a win in this season's tournament. It was England's ninth loss in their last 12 Tests.
But they made unbeaten tournament favourites Ireland fight every inch of the way for a win that was in doubt until deep into the second half.
Ireland, who will tackle Wales in Cardiff on March 19, needed a superb 58th-minute try from captain marvel Brian O'Driscoll to finally see off England.
Fly-half Ronan O'Gara celebrated his 50th cap by booting 14 points - two drop-goals, two penalties and a conversion - as he passed 500 international points in the process.
Number eight Martin Corry scored an early England try, and fly-half Charlie Hodgson, who recovered superbly from his goalkicking nightmare against France, booted eight points, including a 50-metre penalty.
But the end result was still the same, another England reversal, and coach Robinson now has to pick his players up for low-key Twickenham encounters with Italy and Scotland later this month.
Once again, he could not fault their commitment and effort, but they have lost the winning habit.
Ireland, meanwhile, march on in pursuit of a first Grand Slam since 1948.
They entertain France next Saturday, then travel to Wales seven days later, and excitement in the Emerald Isle is at fever pitch.
The RBS 6 Nations Championship 2015 was not poised to go down as one of the more "vintage" Championships, though there was great anticipation as the action headed into its final day. What transpired was something that nobody could foresee: "The Greatest Day in Rugby's Greatest Championship."