Speed kills: Brian O'Driscoll is tackled just short of the line by Harlequins' Ugo Monye and David Strettle

Easter Sunday is an important milestone in the calendar to take store of things. Most of my family came for Easter dinner. Prior to the agreed time, my mother had gone for a walk up Killiney Hill and halfway up she had to sit down and catch her breath. The walk is steep enough, but the exercise did the job and worked up a good appetite. I reminded her that at the start of pre-season training Leinster go to Killiney Hill and from the gate they run up to the very top and jog back down. They don't as much run up as race up and they do it 10 times in a session.

Having my ample bottom pole-forked by adolescent demons in the flames of hell would seem an easier punishment. The professional rugby player works hard for his money. I just wonder how much of an appetite does it stoke up. The Leinster squad are dining now at the top table;­ you would just have doubts that a knife and fork would present too much of a challenge for them. Leinster are where they want to be, where is their appetite?

I just got the impression that if Leinster had lost to Harlequins, and I'm still bamboozled to know how they didn't, that it wouldn't have taken them too long to get over the defeat. The usual malarkey about "lads hurting in the dressing room" etc. How Leinster managed to play quite so badly and still win... well the 6-5 scoreline tells a multitude.

Let's start with defence. Pundits and people have said that Leinster defended well last Sunday. The pressure of conformity elicits a general acceptance that Leinster defended well. Well, bollocks to that, Lumley. The perception abounds that there were fewer holes in Leinster's line than Ray Charles' dart board. If Leinster defended so well, answer me this: Where exactly did they defend so well? In the scramble and in the last ditch tackles close to their own line I hear you say. If Leinster spent a lot of the game scrambling, particularly in the second half, it means that they weren't making their first-up tackles on the line in the first place. In my match notes there were so many Harlequins line-breaks I stopped jotting them down and Leinster's line was soft, particularly in midfield. This game could have been won easily if Leinster had stopped the runner on the gain line. Yeah, Jordan Turner-Hall, Ugo Monye and David Strettle are difficult opponents but it was always the second or third tackle which brought them down when the first was the easiest to make. If Leinster's front-line is as yielding against Munster...

Leinster didn't score a try against Harlequins, neither did they score a try against Edinburgh in January. Wasps too in Twickenham was a fruitless exercise in terms of getting over the whitewash. How can a team with such ability behind fail to get over the try-line?

I flicked back over the pool game against Wasps in the RDS in October where Leinster were scoring tries for fun, six in total. They were irresistible that day – the verve, the brio, the audacity of imagination. The confidence. As a unit has this back line lost its confidence? Yes it's true that they can only play with what's given to them by the Eeyores, but they are guilty of trying to run off slow ball or when they are out-numbered by defenders in the line.

One of the things that I think is symptomatic of their lack of confidence is the number of forward passes, not just in the game on Sunday but over the course of the season. Whether it is poor execution or the support player over-runs it has happened too many times – it is too costly. Felipe Contepomi's pass to Isa Nacewa and his pass back in to Rob Kearney should have been a try. Don't care what anyone says – you don't have to force the pass that close on the gain line. It could have cost Leinster, it was one of two chances that came their way. The second was just on the stroke of half-time and again indicative of the state of Leinster's back play that it was an obtuse moment of individual brilliance, rather than a collective effort that got them close to the line. Brian O'Driscoll read the bounce brilliantly, such was his anticipation and certainty that he accelerated onto it and that was what got him away from the adjacent cover.

Monye and Strettle are probably the fastest wingers in the Premiership and Monye is possibly the fastest player in rugby union. O'Driscoll and Leinster were unlucky that it was these two who were chasing him. Monye screamed in and O'Driscoll's hand-off and momentum would normally have been good enough to score from the position he was in but Strettle's tackle, superior body placement and defensive nous were staggering. The best double tackle I've seen in a long time. The ball was live and O'Driscoll recycled quickly. The ball was three inches from the line as Malcolm O'Kelly came and took six or seven seconds off the ball. Yes, a hand held him but a rollover and he was in. He looked like he was trying to lay an egg. The ball came back though and with no one, not one Harlequin on the openside, and 35 of them on a narrow blindside, Chris Whitaker elects to go on the blindside where they were queuing up to give away a yellow card. Nick Easter obliged and my blood pressure went up a notch.

In the 26th minute something happened on the park that I didn't quite believe so I replayed it on the video twice just to be sure. Luke Fitzgerald made a good run down the left-hand side, he was tackled and the ball was recycled. Whitaker took the usual two or three steps out of the ball. That's a given these days, but that wasn't the crime, the real crime was that he couldn't get the pass away off his left hand and he got spoiled and caught in the act of turning his body around so he could get the pass away off his right hand. Come on! It's a Heineken quarter-final. In mitigation, he put his body on the line more than a couple of times and must have had the highest tackle count on the field.

The stats showed that in the 52nd minute Leinster had effected 14 turnovers to Harlequins' four. This was keeping Leinster in the game. The anorak taking count of the figures would not have been able to take into account other turnovers given by Leinster – but O'Driscoll (7 mins), Nacewa (11 mins), Contepomi (22 mins) and Fitzgerald (31 mins) all kicked hard-won possession directly to touch. Unpardonable.

The key to the game was Nick Evans. The Kiwi's leg was not right from the start but he got away with it for 22 minutes until he collided with Jamie Heaslip. Prior to that he tantalised the Leinster defence. Leinster were like midgets at the urinal, on their toes all day trying to see which channel he would come down – himself or whoever he would release. As soon as Leinster realised that Evan's leg was bunched, Turner-Hall, who had been a big problem for the first half an hour was put back in his box. If Evans had been fit for the 80 minutes Harlequins would have got dividends, particularly from the 72 per cent possession that they enjoyed in the second half. Leinster lived on their wits and looked like closing the game out until Bernard Jackman in the 77th minute decided to try and win the Paddy Wallace Daft Bastard Award for Stupidity by wandering in offside with the ball held at the base of the ruck. Incredible! Harlequins couldn't profit and the match finished breathless.

It is significant that there are three Magners sides in the last four and it gives another marker to note how overrated the Premiership really is. Leinster it seems to me are not playing like a team that are bothered about winning this competition. In two weeks' time they play a team who are. Six weeks later they will be running up and down Killiney Hill wondering why they are going through all this pain again. Appetite, I think.