Six Nations kings Ireland made it a St Patrick's Day to remember by beating England 24-15 at Twickenham on Saturday to seal just their third Grand Slam.
Some 70 years since they completed their first clean sweep in the old Five Nations, Ireland matched their 1948 and 2009 predecessors with another Championship clean sweep.
At a bitterly cold Twickenham - lines on the pitch had been painted blue so they would stand out against the unseasonal snow - converted tries from Garry Ringrose, CJ Stander and Jacob Stockdale gave Ireland a commanding 21-5 half-time lead in front of a capacity crowd of more than 82,000, with Conor Murray adding a penalty on the hour..
England's Elliot Daly scored a try in each half and fellow wing Jonny May went over with the last play of the game but by then Ireland fans everywhere were already celebrating.
Ireland's first win at Twickenham since 2010 left captain Rory Best as one of only two double Irish Grand Slam winners alongside fullback Rob Kearney.
"This feels more special, not only because I have started every game but also because of captaining the side," said Best.
"Every kid grows up dreaming of playing for Ireland, but to win something while captaining in that special green jersey is the stuff that dreams are made of," the hooker added. "It's the biggest highlight of my career."
Ireland kicked off having already secured their third Six Nations title in five years under coach Joe Schmidt.
The New Zealander was especially pleased Saturday by a defensive effort masterminded by defence coach Andy Farrell -- the father of England fly-half Owen.
"That eight minutes after half-time today totally summed up this team," Schmidt said. "We've scored a lot of tries this year, but that pure resilience, the ability to get back up in the defensive line, that was exceptional."
Yet but for Jonathan Sexton's stoppage-time drop-goal on the back of a 41-phase drive in a tournament-opening 15-13 win over France, there never would have been an Irish Grand Slam in 2018.
"To show the steel that they did, the commitment and just plain, ordinary rugby ability to keep the ball," recalled Schmidt. "And then the exceptional ability Johnny has to put the ball between the uprights."
Stockdale's try saw him set a new record in the Six Nations era of seven in a Championship season and meant the 21-year-old Ulster wing now had 11 in just nine career Tests.
"They are a good tough team, very worthy Grand Slam champions and they've performed extremely well today," England coach Eddie Jones offered.
This was England's third straight defeat after away losses to Scotland and France and a first at Twickenham since Australian coach Eddie Jones took over following their 2015 World Cup debacle.
With Wales edging France 14-13 in Saturday's final game of the tournament, it meant England, champions in each of the past two seasons, ended up in fifth place - their worst finish since they came bottom of the old Five Nations in 1983.
The trio of defeats have cast doubt on England's chances of dethroning New Zealand at next year's World Cup in Japan but a defiant Jones said: "Every team I have had that has been a champion team has had these runs and they are instrumental in how you remake a team."
Ireland kicked off having already secured their third Six Nations title in five years under Kiwi coach Joe Schmidt.
By contrast, England came into the game on the back of successive away defeats by Scotland and France, with Jones making 10 changes to his starting XV following last week's 22-16 loss in Paris.
Tries: Ringrose, Stander, Stockdale
Cons: Sexton 2, Carbery
Tries: Daly 2, May