Ireland have been crowned Six Nations champions with a match to spare after England's hopes of retaining the title ended with their 22-16 loss to France.
Ireland's earlier four-try, 28-8 win over Scotland had left England needing a bonus-point victory in Paris to keep their title hopes alive.
It is Ireland's third title in five years under Joe Schmidt but Johnny Sexton said celebrations were "muted".
They will win the Grand Slam if they beat England next Saturday.
"It's a strange feeling to win the championship with a game to go," said Irish fly-half Sexton.
"We know how difficult it will be [to win the Grand Slam]. The shoe is on the other foot from last year [when Ireland ended England's Grand Slam hopes with victory in Dublin on the final weekend] and I am sure they will be licking their lips."
'Twickenham will be massive game'
If Ireland win in London they will secure the third Grand Slam in their history, following previous triumphs in 1948 and 2009.
"It's going to be a big game for us now," said Ireland captain Rory Best.
"Whenever you put yourself in the position to win everything in the Six Nations it becomes massive, but the key for us it approach it as we do every game.
"We are going to have to save the best till last. That's what it's going to take to win everything next week."
|Outright Championship wins since 1883 (shared wins)|
|England - 28 (10)|
|Wales - 26 (12)|
|France - 17 (8)|
|Scotland - 15 (9)|
|Ireland - 13 (9)|
|Italy - 0 (0)|
Stockdale strikes twice - how the day unfolded
Ireland began the day five points clear of England at the top of the Six Nations table.
Schmidt's side knew a bonus-point victory in Dublin would require England to do the same in Paris to keep the title race alive - and the Irish secured the five points with ease.
Winger Jacob Stockdale, the 21-year-old playing only his eighth game for Ireland, bagged two tries to take his overall international tally to 10, while further scores from Conor Murray and Sean Cronin handed ruthless Ireland a thumping win.
So it was over to England, in the later game in Paris, to take the title race to the final weekend.
England hopes ended by France
England travelled to the Stade de France hoping to avoid two successive defeats for the first time under head coach Eddie Jones.
They had been comprehensively outplayed by a fired-up Scottish outfit at Murrayfield in the third round, and kicked off in Paris knowing only a bonus-point victory would be enough to deny Ireland the title.
Before the match, Jones told BBC Sport his side had not discussed bonus points and permutations, and just needed to play well.
With the scores level at 9-9, the match was blown wide open when Anthony Watson's high tackle on Benjamin Fall saw the England full-back yellow carded and a penalty try awarded.
Jonny May's late try gave them hope of an unlikely win, but France held out against a white-shirted onslaught at the death for only their second win in a year.
Key moment of the tournament - Sexton strikes in Paris
Ireland very nearly fell at the first hurdle in this year's tournament, but were saved by Johnny Sexton's last-gasp drop-goal in Paris.
The Irish fly-half landed a dramatic long-range effort in the 83rd minute to snatch victory over France on the opening weekend in February.
Former British and Irish Lions centre Jeremy Guscott said it would go down as "one of the great sporting moments in Six Nations' history" if Ireland went on to win the Six Nations.
"It was a very special moment for the team," Sexton said of his drop-goal.
"We will look back on that five minutes [Ireland's 41-phase move to set up Sexton] when we lift the trophy next week, hopefully with a Grand Slam, and say it was a huge moment in our success."
Source: BBC Rugby Union News