Peter O'Mahony made the most of a late call-up to lead a superb defensive effort as Ireland beat England 13-9 to deny the visitors a record-breaking Grand Slam victory in Dublin on Saturday.
Had England, who'd already won a second straight Six Nations title, come out on top they would have surpassed the record of 18 consecutive Test wins they share with world champions New Zealand and become the first side in the Six Nations era to complete back-to-back Grand Slams.
But Ireland, who ended the All Blacks' winning streak with a 40-29 win in Chicago in November, proved too strong at a rainswept Lansdowne Road.
They scored the only try of the match when lock Iain Henderson went over in the 24th minute, with the rest of their points kicked by fly-half Jonathan Sexton.
All England, who ran in seven tries during last week's 61-21 rout of Scotland, had to show for their efforts were three Owen Farrell penalties as they suffered their first defeat under Australian coach Eddie Jones.
"Ireland played superbly and they were too good for us on the day," said Jones.
"My message to the (England) team was be proud of yourselves. They are back-to-back Six Nations title winners and joint world record-holders.
"We're batting at a pretty good average," said lifelong cricket fan Jones before adding: "Even Don Bradman got a zero in his last Test."
Victory saw Ireland retain their top four position in the world rankings ahead of May's draw for the 2019 World Cup.
"The bit of pride we can take is the three teams that sit above us in the world (New Zealand, England and Australia) we have beaten in the last six months," said Ireland coach Joe Schmidt.
O'Mahony, who only started after fellow back-row Jamie Heaslip was ruled out after rolling his ankle in the warm-up, exemplified Ireland's display, with his line-out steal six minutes from time denying England a potentially match-winning try.
"Credit to Ireland," said England captain Dylan Hartley.
"We seemed to back up every error with another error," added Hartley, also a member of the 2011 England side whose bid for a Grand Slam ended with a Dublin defeat.
"We are not the finished article. This will keep us grounded."
Ireland captain Rory Best, vying with Hartley to be the British and Irish Lions starting hooker on their tour of New Zealand this year, was deligted with his side's response after a 22-9 loss to Wales in Cardiff last week ended their title hopes.
"We knew it would take a monumental effort to stop a quality outfit," he said.
"Big occasions, big men rise to it and we certainly had a lot of those," added Best after a win that saw Ireland finish second on points difference.
Three times before in the 2000s had England arrived in Dublin just one win away from a Grand Slam but only on one of those occasions, their World Cup winning year of 2003, had they come away with the cherished prize.
- Ferocious Ireland -
Ireland made a ferocious start and they nearly had a try in the ninth minute.
Best, with a reverse pass worthy of a centre, found Jared Payne, who passed to Keith Earls only for the wing to knock-on under pressure from England's defence.
But England had infringed and Sexton kicked opened the scoring with a simple penalty.
Farrell, whose father Andy is now Ireland's defence coach, drew England level after an Irish ruck offence.
Irish playmaker Sexton, often the recipient of rough treatment, was tackled late in the 20th minute by Maro Itoje.
Sexton kicked the resulting penalty deep for an attacking line-out.
Ireland battered away at England's line, with No 8 Billy Vunipola conceding a penalty.
Rather than go for goal, Ireland opted for a line-out just five metres out.
Best found his man and from the catch and drive, Henderson, chosen ahead of Devin Toner, stretched out for a 24th minute try.
Sexton converted and Ireland led 10-3.
Farrell cut the lead to 10-6 with a 47-metre penalty early in the second half.
England remined four points down heading into the last quarter.
If ever they needed their replacements or "finishers" as Jones calls them, it was now.
But instead Sexton, hit by another late tackle, extended Ireland's lead with a superb long-range penalty from wide out on the left.
Farrell's third penalty made it 13-9 but that was as close as it got, with Hartley collecting the Six Nations trophy on the back of a defeat.