Ronan O’Gara may have kicked all of Munster’s points but his rival for the Ireland number 10 jersey, Jonathan Sexton, had the final say at Thomond Park as his Leinster side prevailed in a titanic Magners League tussle.

Having missed a penalty just two minutes earlier, Sexton held his nerve to convert a 66th minute penalty and drive Leinster to their first win at the Limerick venue since 1995 and their third successive triumph over their arch rivals.

It has given Michael Cheika’s men a seven-point advantage at the top of the Magners League, and serious momentum ahead of next weekend’s Heineken Cup quarter-final showdown with Clermont Auvergne.

The result owed much to Leinster’s watertight defence and territorial dominance as the game wore on, with full-back Rob Kearney’s late first half touchdown proving to be the only try on the night.

O’Gara, Munster’s captain in the absence of the injured Paul O’Connell, had a 100% kicking return with five successful penalties, but it was not enough as Sexton and Fergus McFadden landed three penalties between them and the former converted Kearney’s try.

Having recently lost his starting place in the Ireland team to Sexton, O’Gara’s eagerness to impress was seen in the opening seconds when he charged down his opposite number.

In a raucous atmosphere, Munster seized the early initiative with an O’Gara penalty punishing a binding offence from CJ van der Linde, and the latter’s Springbok colleague Jean de Villiers featuring in a thrilling right wing raid.

Munster were varying their attacks well and when Leinster captain Leo Cullen saw yellow in the 14th minute for a deliberate knock on, O’Gara gave the hosts a deserved 6-0 lead.

However, the numbers were evened up three minutes later as Donncha O’Callaghan was sin-binned for slapping the ball out of Shane Jennings’ hands at a ruck, and Sexton landed the resulting penalty for Leinster’s opening points.

The first half was largely free-flowing but there was a typically hard-edged element to this interprovincial clash and a needless check by Girvan Dempsey on de Villiers allowed O’Gara make it 9-3.

Leinster hit back with a sidestepping break from Gordon D’Arcy and only frantic defending – Ian Dowling stopped Kearney just short of the try-line – kept the visitors out. The attack did produce a second successful penalty, struck by McFadden as Sexton received attention.

O’Gara replied with another fine drive from the left, as Leinster were pinged for not retreating, and it looked to be advantage Munster as Sexton pushed a late penalty attempt to the right and wide.

However, Leinster engineered a smash-and-grab try in the dying seconds of the half as a chip through from Isa Nacewa bounced awkwardly for Tomas O’Leary and Doug Howlett and the advancing Kearney gathered it to crash over in the corner.

Sexton silenced those in the crowd who had been jeering him with a tremendous conversion from wide out, handing Leinster a 13-12 buffer for the break.

Leinster dictated play in the opening stages of a stop-start second period but O’Gara shot Munster back in front, after Nathan Hines was sin-binned for a dangerous tackle on Dowling.

On the hour mark, Leinster went through a series of phases in the Munster half and worked two penalty chances for Sexton, the second of which he slotted from a left-sided position.

The Leinster out-half snatched at a 73rd minute drop goal as he tried to extend Leinster’s lead, and the excitement and tension increased as Munster marched towards the visitors’ 22, with the tireless Alan Quinlan leading the charge.

However, a knock on between O’Gara and Lifeimi Mafi undid all the good work and Leinster, with Nacewa almost getting through for an intercept try, were able to soak up the pressure in midfield and see out a deserved win.

Speaking after the game, man-of-the-match Jamie Heaslip said: "That was right up there with any international match in terms of intensity. It’s always nice to beat Munster, but we know that it was a battle and we just came out on top.

"We have faith in our defence and we didn’t panic and there were confrontations all over the pitch. We’re not going to let this win go to our heads.

"Although it’s good to have a bit more space between us at the top of the league, we have a lot of hard games coming up, particularly next week’s one against Clermont Auvergne."

A disappointed Donncha O’Callaghan admitted afterwards: "They’re a quality team to be fair to them. There’s no excuses, we were out-played tonight, it’s just so disappointing.

"This has got to hurt and this has to drive us on. There’s no point moping around and feeling sorry for ourselves for the week."