Heineken Cup 2012: Proud Irish lead passion play Brian O'Driscoll against Aurélien Rougerie, Rob Kearney against Lee Byrne, Isa Nacewa against Sitiveni Sivivatu. This will be a high-quality experience as befits the status of the tournament at this stage. There will be drama and heartache no matter which of the matches you consider, though we're unlikely to witness the agonies we saw at the Millennium Stadium in 2009. It was 26-26 at the end of extra time, which left Cardiff Blues and Leicester to decide who would have to take penalty shots at goal from in front of the posts. If Real Madrid's players struggled to hit the mark in their Champions League semi-final in midweek, highly-paid professionals supposedly used to nerve-shredding occasions, then it was no surprise that ad hoc rugby kickers should find difficulty in knocking the ball over from 22 metres. It was ghoulish yet riveting, with one of Wales's finest, flanker Martyn Williams, making a mess of things to leave Jordan Crane with his pot at glory which was duly landed to see Leicester into the final, 7-6 on penalties. The system was changed as a result of those public agonies. In a similar situation this weekend, with scores level after extra time, three players from each side on the pitch at the final whistle will take kicks from varying positions. You might hope (or perhaps not) that it will not come to that, yet both matches look as if they will be close. It's hard to pick a clear favourite in either tie. Edinburgh are an unlikely semi-finalist, through for the first time ever, as are Clermont. Yet there is less surprise that Les Jaunards should have finally made it here. Edinburgh have had a wretched season in the Pro12, a return of only five wins in 21 games, yet their form in Europe is Jekyll-esque: from a rather outrageous 48-47 victory over Racing Metro 92 in their Pool 2 match to a notable 19-14 quarter-final win over four-time champions Toulouse at Murrayfield. There was a record attendance of 37,881 there that day. Given that crowds north of the border have often been calibrated in men and dogs, that figure in itself was a miracle. Quite whether Michael Bradley's team can continue to defy logic will depend on sustaing the enterprising brand of rugby that has taken them so far. Ulster's revival, reaching this juncture for the first time in 13 years, lends another unpredictable element to the event. Can they sustain the fury and cleverness that took them to a huge home win in the pool stage over Leicester (41-7) and on to a remarkable quarter-final triumph over Munster at Thomond Park? The face-off between the back-rows will be crucial, with Edinburgh's David Denton looking to subdue Stephen Ferris. Leinster are aiming to become the first team since Leicester a decade ago to win back-to-back titles. They are well-equipped to do just that, an all-court side, with power upfront and potency behind. So, too, though, are Clermont. A weekend rich in promise awaits. Up above, Richard Harris will be casting envious glances.