A long way down: Leinster's Shane Horgan and Rocky Elsom tackle Lifeimi Mafi of Munster during last weekend's Heineken Cup semi-final at Croke Park

Well, were we prematurely disappointed in last Saturday's outcome? Leinster, high on talent and talismanic pedigree but low in temperament and 80-minute toughness, were to be gutted and filleted, plucked and stuffed. Sometimes turkeys duck. I have a paralysing suspicion that Leinster borrowed heavily from their southern neighbours' lexicon of persecution complexes and came onto the pitch feeling like a One 'n' One from Burdock's. Anger is an energy. I never saw it coming. In my preview I said too many 'ifs'. They got it right and pulled out a measured performance which, given the magnitude and consequence of the game, represents their best ever performance.

The Heineken Cup is a long journey and they've had to weather a few storms even in getting out of the pool. Maybe too the need for recognition for their travails fortified them. If Columbus had turned back no one would have blamed him… or remembered him either. This class could have given up but, credit to them, they persevered. For some of them it represents their sole chance of decoration and of having their names remembered within the pale.

Whether it was desperation or inspiration that provoked a subtle change in the way they played, it was edifying that the critical scores came from playing rugby through the hands. The first time you cross your opponents' line gives great confidence. The more perceptive of you might have guessed it, but Leinster's first try was the same as O'Driscoll's in the France game. Yes, he scored near the sticks and D'Arcy scored in the left hand corner but the principle was the same.

The genesis for Leinster's first try came from somebody who wasn't even on the pitch at the time but who was key to Leinster's win. Felipe Contepomi, cruelly robbed by a pitch that gives too much when a player changes course, was going to put his charismatic signature on this match with a virtuoso performance. It is a matter of great regret that he did not play the full 80 and even greater that he will not play in Murrayfield in two weeks time.

Contepomi had a vital role to play in giving opportunity to those outside and his and Leinster's thinking demonstrated this from the first play of the game when the Argentine took his first running ball, ignored outside and went straight down the 10 corridor. Ronan O'Gara happened to be standing in the middle of it. He looked like one of 10 pins that is hit by a bowling ball. O'Gara was knocked on his arse, legs in the air and run over. David Wallace, powerhouse that he is, had to divest most of his considerable strength in trying to restrain the Argentine. The gain-line breached and 12 metres garnered in the run, Leinster's forwards milled through and recycled. From the first minute, Wallace knew he'd have to be on guardian angel duty as Contepomi decided that he would take the game to O'Gara on his terms and in the most physical way.

About 10 minutes later, Contepomi dinked over O'Gara's head and collected. Munster, who had been quick up, had to scramble back to stop him. Ten minutes later Contepomi ran straight into O'Gara and Stringer again in the narrow channel, so everyone had to check and turn back in to deal with the cut. Leinster were now primed to do damage because Munster had to check for runners on the inside channel.

From a 25th-minute line-out Contepomi received good ball from Chris Whitaker (he has stopped taking a step and his delivery and accuracy were tremendous). Wallace, out of necessity, had already moved in front of O'Gara to take Contepomi and Munster's spread of auxiliary tacklers into midfield consisted only of Marcus Horan. Shane Horgan, who crucially had come in off the right wing, pushed in and back into Horan pretending to take the ball from O'Driscoll and Rocky Elsom screamed into the breach like a bat out of Moyross. He normally has the pace and energy to score but Paul Warwick corralled him well and forced him to step which made for a easier tackle.

From the recycle Munster conceded a penalty which Sexton put away. Contepomi was off the field but he had grievously upset the certainty that Munster had in defence. They would open them up again five minutes later and it would be a carbon copy of O'Driscoll's try against France (and all credit to Alan Gaffney on that score).

In the France game Ireland won ball off O'Connell at the line-out, Thierry Dusautoir wasn't checked by O'Gara off the back of the line-out, Paddy Wallace at inside-centre drifted outside to leave Brian O'Driscoll coming onto the ball from outside centre and running at Lionel Beauxis. Meanwhile Tommy Bowe came in off the right and was timing his run to fit in outside Wallace's position. Rob Kearney was coming in on the diagonal looking for a flat pass. The move didn't come to full fruition because Beauxis missed his tackle and O'Driscoll kept going, stepping Julien Malzieu to go over the line.

Leinster took line-out ball from a magnificent, full-leap, finger-tipped pull down from Mal O'Kelly and again Whitaker's pass to Sexton was fast and direct. Munster drifted as Sexton took the ball. The same play came about. D'Arcy drifted out from inside centre behind O'Driscoll who came onto the ball. Horgan, as the move decrees, had come in off his wing outside D'Arcy. Nacewa had only just started his run. O'Driscoll was heading back into O'Gara's territory. The whole of Munster stopped except for Keith Earls who kept going, sure that the action would happen inside but just in case he'd cover D'Arcy and Horgan who had wrapped around outside. He left a gaping dog-leg as he went two metres further than the line. O'Driscoll knew that Mafi had him in his sights and did not try to line-bust. He stopped, flat-passed to Nacewa (it was marginally forward) the pace and angle was decisive and the Fijian line-busted in spectacular fashion. The dummy sizedWarwick up and the pass at pace took him out of the game. Earls would have caught D'Arcy properly if the pass had been anything less than perfect. D'Arcy couldn't afford the luxury of a check. 11-3, game on.

Leinster's second try was a measure of their confidence. Three times across the pitch with real confidence in what they were about. It looked like a simple passing movement and yes Horgan's quick hands to Luke Fitzgerald were important to take Ian Dowling out, but I thought Nacewa's intervention was key. His pace into the line and the quality of his pass beat two men and checked the line. Fitzgerald's step at full pace was far harder to execute than you would imagine. 18-6, game still on.

Munster began to retain and started pounding on Leinster's door with 20-25 minutes to go. Could you imagine if instead of ceding an intercept Munster had scored to make it 18-13 with 20 minutes to go? Where would your money have been placed at that stage? It didn't happen.

But the question you have to ask yourself is: Why is it always O'Driscoll? How was it that only he could see the intercept coming and be in position for it? Why or how did he decide to take the ball on close to the line and score in the England game? How come he managed to chase down Phil Godman and Thom Evans in the Scotland game? How come he just happened to be loitering with intent at the back of a ruck in the Welsh game to get Ireland's first try? Champion's instinct. The contest and result ended on the 60th minute because of him. Leinster could enjoy themselves, denying Munster even a try for pride.

Look down the page at the other pillar of Leinster's success, their offensive defence. The stats are a roll of honour. It's hard to digest the scale of Leinster's resolve, they can only be extrapolated from figures shown in the tackle. Leinster made an astonishing 203 tackles in 80 minutes, over twice as many as Munster. Some have to be picked out for merit.

D'Arcy's performance was a revelation. I've seen him over-exert himself in some of this year's Magners games to try and kick-start some form, not with a huge amount of success. It's not pretty watching a great player doing this. True, he picked up a Grand Slam in the end, but he really needed this match to find his mojo. Tom Shanklin is unfortunately out of the South African tour and based on his performance last Saturday D'Arcy will walk in. D'Arcy made 17 tackles in midfield, more than the combined total of the Munster three-quarters (they had the ball). It wasn't the quantity as much as the quality and intelligence – nobody did more to retard the speed of the ball from the tackle zone than Leinster's inside centre. Munster's offload game was stymied by his positioning.

The quality of Jamie Heaslip's tackling was tremendously effective also. At vital moments in his own 22 in the second half he stopped Munster's rhythm at source and aggressively drove them back. Leo Cullen too had a productive afternoon. I had under-estimated Shane Jennings' contribution in the match, 23 tackles in 80 minutes is outstanding and on even closer review many of Leinster's turnovers can be attributed to Jennings. He had a big game in a dominant Leinster back row and more of the same is required.

Michael Cheika got a lot right. The conditions though were primed for an upset. The fickle nature of sport demonstrates the fine line between success and failure. If he had lost this one game he was gone. Now that his team won it's a different vista. Using criticism as a motivational tool is not sustainable now and the Leinster game requires a different approach. Still the question though, is he lucky or is he good?

Meanwhile, if Leinster are serious about winning this competition they will have to get their line-outs sorted. In all the hullabaloo, everybody missed the fact that Bernard Jackman conceded seven turnovers at line-out time.

PS Leinster's uneven form throughout the season drew effusive praise and heavy criticism from me which can be reviewed on the links below.


14/12/08 - Leinsters Lacklustre

21/09/08 - Right here right now for Leinster