Ireland face England in a winner-takes-all clash at the Aviva Stadium on Sunday.
The Red Rose are looking to end a 10-year losing streak in Dublin, while there is also plenty at stake for British and Irish Lions candidates in both sides.
Ireland's strengths/England's weaknesses
Home advantage should give Ireland a mental edge. Declan Kidney's men showed their battling qualities in the second half against Wales as the visitors were forced to make some mind-boggling try-saving tackles to protect their lead. With the fans roaring Ireland on, the motivation to beat the Old Enemy will be stronger than ever.
How will England approach the game? Much has been made of their so-called arrogant streak - at least by Scotland. It could be simply gamesmanship by the Scots but their historic victory over New Zealand last autumn coupled with the Calcutta Cup success may result in complacency seeping in - although that is unlikely with Lancaster at the helm.
More significantly, England haven't won in Dublin since 2003, and if Ireland make a blistering start, it will be interesting to see how Chris Robshaw and co cope. They could struggle.
Ireland also have the more experienced players in key areas - Rory Best at hooker, Jonathan Sexton at fly-half and Brian O'Driscoll and Gordon D'Arcy in midfield - and if they can win these battles, it could tip the scales in their favour.
England's strengths/Ireland's weaknesses
England's scrum appears to be their major strength, with questions marks lingering over Mike Ross's fitness. Last year, the Leinster tight-head prop lasted 35 minutes before being replaced by Tom Court at Twickenham, and it proved the turning point of the match, as England's Alex Corbisiero, Dan Cole and Dylan Hartley spearheaded a rout, with 27 of the Red Rose's 30 points originating from mistakes by the Irish scrum.
Last week in Cardiff, Ireland's pack performed well, although once again, Ross's substitution in the 55th minute led to their Welsh opponents getting on top. This year, Kidney will most likely look to Declan Fitzpatrick, who is lacking match fitness, and should Ross need to be replaced, it would be a major concern for Ireland - and a huge boost for the visitors.
England are also strong in the breakdown and their ability to getting quick ball. In particular, Ben Youngs excels here, and Danny Care if he comes on. The pair was in good form against Scotland and Ireland must look to disrupt such play.
There are a number of intriguing match-ups which British and Irish Lions head coach Warren Gatland is sure to be watching closely. For many, it's an audition for the Australia tour. Rory Best and Dylan Hartley - the latter on the bench for England - are two candidates hoping to fill the hooker role.
Hartley is a formidable opponent and one who Lancaster may look to bring on to disrupt the Irish scrum, although Best proved more than capable of handling the South-African born hooker in Ulster's clashes against Northampton Saints in the Heineken Cup this season.
Another intriguing clash sees Jonathan Sexton and Farrell come face-to-face. The Leinster fly-half is leading the race to fill the No.10 Lions jersey, but Farrell, just 22, has rarely put a foot wrong since stepping up to the England side in the Six Nations last year.
Finally, there are the two standout candidates for the Lions captaincy: Brian O'Driscoll and Robshaw. The 34-year-old may not be Irish captain, but as he proved last week in Cardiff, he's lost none of his influence, while Robshaw is facing perhaps one of his toughest tests since taking up the role - and he's had his ups and downs as skipper.
Ireland need to play in the same manner as they did against Wales in the first half at the Millennium Stadium, but for an entire 80 minutes. This England side are very dangerous and can punish Kidney's men. England haven't won in Dublin since Martin Johnson irritated an entire nation with his pre-match antics before leading his side to the Grand Slam... expect Ireland to rise to the occasion of a home tie against the Old Enemy and edge to victory - just. Ireland 14-13 England