Brian O'Driscoll is wary of the threat "bullish" Wales pose to Ireland's hopes of setting up a potential Six Nations decider against England in Dublin next month.
Defending champions England's trip to the Aviva Stadium on the final day stood out as a clash that could settle the tournament when the fixtures were released.
England are still in the hunt for a second successive Grand Slam following victories over France and Wales, which has given them a two-point advantage ahead of their meeting with Italy this weekend.
Ireland were seen as the team most likely to dethrone Eddie Jones' men, but slipped up against Scotland in their first game of the tournament before putting Italy to the sword in Rome.
Joe Schmidt's side host France on Saturday before travelling to the Principality Stadium and Ireland legend O'Driscoll said they cannot afford to ponder the possibility of a winner-takes-all showdown with England on March 18.
Speaking on behalf of Land Rover, O'Driscoll told Omnisport: "To have France at home and Wales away before you can even start thinking about that is a lot.
"What you would perceive to be the two easier games in Six Nations being first up and you lose the first one, it's a long way back from there.
"But it wouldn't surprise me if there was the championship at stake for both teams in the final round. It looks like it will be for England on the day.
"There is a lot of rugby to be played, but France at home will certainly not be easy and I think Wales will be a really tough one with the way they played against England.
"Wales get bullish in Lions years, it will be a big thing if they lose two matches at home."
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