Ireland took full advantage of a red card for England lock Charlie Ewels after less than two minutes of Saturday's titanic Six Nations encounter at Twickenham to claim a bonus-point 32-15 victory that keeps them in the hunt for the title.
Ewels was sent off for a head-on-head tackle on Ireland second row James Ryan and Ireland led 15-9 at halftime after tries for James Lowe and Hugo Keenan.
England hit back superbly to level the match via Marcus Smith's boot in an amazing atmosphere but Ireland finished strongly as tries by Jack Conan and Finlay Bealham earned a potentially key bonus point.
France top the standings on 18 points after winning their first four games and will take the Grand Slam with victory over England next week.
Ireland have 16 points and could still take their first title since 2018 with victory or possibly even a draw against Scotland in Dublin if England can upset France in the final game of the championship. A French draw could also be enough for Ireland to top the standings with a win.
"We showed today how much it means to be part of this team. We didn't give up for a second," England captain Courtney Lawes said.
"We knew it was going to be tough from minute two. As soon as the red card went up the energy went up -- but we were pretty tired at the end."
The eagerly-awaited showdown appeared to be effectively decided with 82 seconds on the clock when Ewels' upright tackle on opposite number James Ryan gave the officials no room for "mitigation" to reduce the punishment to yellow.
It was the earliest sending off for any team since the championship began in 1883 as Ewels became the seventh England player to be sent off and the first since Elliot Daly early on against Argentina in 2016. England came through to win that game but an in-form Ireland was a different proposition.
After a Johnny Sexton penalty, the dangerous Lowe was given way too much space and crossed for the opening try to give the visitors an 8-0 lead.
England regrouped well forcing a series of penalties enabling Smith to get it back to 8-6, only for a great running line by fullback Keenan to stretch the lead, which was 15-9 at halftime after another Smith penalty.
England came out full of energy after the break, regularly demolishing the Ireland scrum and hitting rucks with renewed force. It brought huge roars of appreciation from the Twickenham crowd, suddenly scenting a victory for the ages as Smith clipped over two penalties to level the scores after an hour.
They exploded again when Freddie Steward grabbed an interception on his own line and galloped clear for a certain try, only for play to be called back for an Ireland penalty. It proved the turning point of the match as Sexton knocked it over.
Ireland then piled on the pressure and England's gutsy goalline defence eventually cracked when Conan crossed in the corner and Bealham then bundled over for the potentially key fourth try.
It was harsh on England, whose fans gave them a rousing reception -- much more so than after their scruffy victory over Wales two weeks ago -- fully appreciating the monumental effort they put in to stay in the game for so long when so disadvantaged.
But they now go to Paris seeking to avoid three championship defeats for the second year in a row, while Ireland will need to do a job on Scotland then sit back and, if they can, cheer England on in Paris.