IF this emphatic defeat was anything to go by, Leinster's defence of their Magners League title is as good as over. Munster were too strong, too clever and in the end, too damn good as they opened the gap at the top of the table to seven points. Well beaten at the RDS at the start of the season, Leinster were forced to tug the forelock once again. Their attempt at storming the Thomond Park citadel was effectively scuppered when Felipe Contepomi's place-kicking fell to pieces much to the delight of the Munster faithful.

If the destiny of the league was undoubtedly the main prize with Munster looking to open an unassailable lead, and Leinster hoping to add to their seven wins in a row, there were other issues up for grabs last night. Not least, a further skirmish in the civil war that has only intensified since that famous Heineken Cup semi-final in 2006, and you also had the feeling that this was a game that Lions coach Ian McGeechan would surely be casting an eye over.

Not surprisingly, Munster were out of the traps with that little bit of extra venom. It was feverish, intense, just as you might have anticipated, with both defences stretched to the limit. Leinster soon got Rocky Elsom into some open space and the powerhouse flanker was at the heart of one attack which finished with the blue jerseys conceding a penalty. Contepomi had been wide with a penalty – he ended up missing four kicks in all – and just before the interval, Rob Kearney badly scuffed a long-range effort.

The visitors lost Bernard Jackman, whose throwing hadn't exactly been a thing of beauty, midway through the half, and as the silky running of Doug Howlett began to bring Munster some reward, O'Gara was on target with a couple of penalties to create a 6-0 cushion by the half-hour mark.

With the Leinster defenders primed to drift across the pitch, O'Gara went for the gap himself on one or two occasions, but he wasn't able to offload as Contepomi made the tackle. Lifeimi Mafi threatened, and Alan Quinlan and David Wallace also bulldozed their way into the 22.

Leinster revamped their backline not long after the break with Jonny Sexton coming in at out-half and Kearney moving to full-back in place of Dempsey, and if the changes did improve their tempo, Munster were still ticking along pretty nicely. O'Gara tapped over another penalty and then unerringly struck a drop goal from 30 metres after Paul O'Connell had won a line out.

Leinster did manage to create more field position, but critically, Contepomi's wayward place kicking only added to their frustration. The Argentine missed from near the touchline, and then snatched at another doomed penalty attempt. Within minutes of Contepomi's third miss, the game swung inexorably Munster's way with a superb opportunist try by Earls.

The young centre looked to be hemmed in near the touchline, but he handed off Cian Healy and then accelerated past Kearney to plunge over in the corner. There was simply no way back for Leinster.

Gordon D'Arcy's try was slickly created and finished, but Peter Stringer came on and immediately felled Elsom like a logger toppling a redwood as the Aussie thundered towards the line. On as sub for Jerry Flannery, Denis Fogarty added a second Munster try after Barry Murphy's knifing run. Cue more celebrations in the heartland of Munster rugby.

MUNSTER P Warwick; D Howlett, K Earls, L Mafi, I Dowling; R O'Gara, T O'Leary; M Horan, J Flannery, J Hayes; D O'Callaghan, P O'Connell (c); A Quinlan, N Ronan, D Wallace Subs P Stringer and D Ryan for O'Leary and Dowling, 65 mins; T Buckley for Hayes, 67-71 mins; M O'Driscoll for O'Callaghan, 69 mins; D Hurley for O'Gara, 75 mins Sin bin Mafi, 70-80 mins

LEINSTER G Dempsey; I Nacewa, G D'Arcy, S Horgan, R Kearney; F Contepomi, C Whitaker; C Healy, B Jackman, S Wright; L Cullen (c), M O'Kelly; R Elsom, S Jennings, J Heaslip Subs J Sexton for Dempsey, 50 mins; R McCormack and T Hogan for Healy and O'Kelly, 64 mins; J Fogarty for Jennings, 67 mins; S Keogh for Sexton, 67-70 mins; Keogh for Horgan, 76 mins

Referee C Berdos (France)