Wales fly-half Rhys Priestland is in confident mood ahead of Saturday's trip to Dublin to face Ireland in the Six Nations.
The reigning champions head for the Aviva Stadium following a hard-fought 23-15 opening win over Italy at the Millennium Stadium, and Priestland is certain Warren Gatland's side are ready to up the tempo.
The Scarlets stand-off said: "It is a massive challenge, and there is a buzz about the place looking forward to combating whatever Ireland throw at us.
"It will be hostile there and they will be desperate to stop us going for the third title (in succession), and we are desperate to win it.
"We are looking to test ourselves against a very good Irish team which could have beaten the All Blacks last year. We are under no illusions about how difficult it is going to be, the toughest challenge we will face in the Six Nations, maybe.
"The way they have been speaking about the game and the way they should have beaten the All Blacks means they are on a massive high, and it could possibly be our toughest challenge.
"Defensively, we are going to have to be at our best, and we need to improve with the ball in hand from last week, but defences win you championships. It will be a massive test, defensively, to keep them quiet.
"They are the rivals we know best because both countries have four teams in the PRO12 and come up against each other quite often. We are familiar with the way we both play."