Ireland went from playing quite badly in France to then being on fire in the win over Wales two weeks ago.
That will give the team - which shows only one change to the starting XV - confidence as they go to Twickenham to face England.
But how they get on depends on the first 15 minutes of the match.
It will be important that everyone's kept on their toes, and that they keep their discipline. You just can't concede penalties, because Paul Grayson is slotting them over at will at the moment.
It was the case under Martin Johnson, certainly, that England felt they were unbeatable at Twickenham. Whether that same presumption remains under Lawrence Dallaglio we don't know, as this is their first international at home since the World Cup.
I'd expected Ireland's home game against Wales to be close, yet it was anything but. Ireland were ahead after 58 seconds when Shane Byrne ran through one of the biggest gaps I've seen.
I was very pleased for Shane, who scored two opportunistic tries and threw well all game.
The key, though, was the returning Brian O'Driscoll. He offers a lot of possibilities, runs very well and gives the team something they don't have without him.
At Twickenham, Ireland have to get into positions where they can score, and the combination of O'Driscoll and Gordon D'Arcy is key to their ability to exploit situations. They must also kick their penalties when they get them.
England are overwhelming favourites to win, but Ireland have a chance. If they can get their heads around that, and believe they can win, it's possible.