Leinster now have a firm grip on this year's Magners League title after beating Heineken Cup semi-finalists Munster 21-12 at the RDS.
In a tryless game, Felipe Contepomi kicked six penalties and Jonathon Sexton landed a late drop-goal to give the home side a 12-point lead at the top of the table.
Ronan O'Gara kick-ed two first half penalties before being replaced at half time with a twisted knee, while sub Paul Warwick added two more in the second half.
More worrying for Munster fans was the sight of scrum-half Peter Stringer being stretchered off with a stringer injury after a blow to the neck, but the management said it was largely precautionary and are hopeful it's not to serious.
An away win for Leinster in Edinburgh next week would mean Munster and second-placed Cardiff Blues have only a remote mathematical chance of catching them.