The Triple Crown holders needed Scotland to pull off a shock triumph in Paris or for France to win by less than 23 points in the penultimate match of the championship.

Only England could then catch them but the world champions would have to amass a cricket score against Wales to overhaul their rivals, who are in pole position.

Expecting the RBS 6 Nations to be decided by points difference, Ireland produced a stunning display of attacking rugby to land an enormous psychological blow on France.

Their finishing was utterly ruthless with Girvan Dempsey and Denis Hickie running in a brace of tries each while Simon Easterby, Gordon D'Arcy, Shane Horgan and Ronan O'Gara also crossed.

Italy put them under heavy pressure in the first half, and trailed just 20-12 at half-time thanks to the boot of Ramiro Pez, but Ireland were lethal with the ball in hand and their class eventually told.

O'Gara put Ireland in front with an early penalty but Italy were back on level terms through fly-half Pez's drop goal.

Italy edged ahead when Pez landed a penalty but Ireland's reply was swift as they ran a free-kick and Dempsey scored in the corner.

The hosts were hit by a stroke of bad luck as the ball bounced free from a scrum into the path of Peter Stringer and Ireland broke, which led to Easterby crossing in the corner.

O'Gara once again missed the conversion but Ireland had established a 13-6 lead they scarcely deserved, although another Pez penalty and drop goal kept Italy in touch.

Ireland pounced after Italy conceded a free kick as D'Arcy ran in their third try but the score was shrouded in controversy with Hickie's scoring pass to D'Arcy nearly a yard forward.

The visitors came out with all guns blazing after half-time as D'Arcy ran a quick penalty, recycling to O'Gara who sent Dempsey through a large gap and over the line, with the fly-half adding the conversion.

The flood-gates had opened as Ireland ran in their fifth try with Hickie slicing through Italy's midfield and picking out Horgan to race home unchallenged.

Hickie crossed himself following a crafty dummy and then O'Gara went over, chasing a kick after D'Arcy had broke from his own half.

Brian O'Driscoll was helped from the pitch with an injury before Italy skipper Marco Bortolami crashed over after gathering a crossfield kick from Andrea Scanavacca, but Ireland restored their 30-point cushion with a late try from Hickie.

There was still time for Roland de Marigny to score in the corner with Ireland refusing to kick the ball out when in possession and then seeing their points advantage further reduced by Scanavacca's conversion.