uccess in rugby is generally mined from the painful depths of failure. Look at the most recent European champions and a glint of silverware has been the product of years of toil. Saracens, champions for three of the past four seasons, endured a three-year period when they regularly finished second in big knockout games. Leinster, currently seen as firm Champions Cup favourites, finished rock bottom of their qualifying pool only four years ago. It is almost as if all high-achieving club sides require a lengthy incubation period, with the exception of big-spending Toulon who remain one of only two teams – with Wasps in 2004 – to have won the competition having been in the Challenge Cup the previous season. More often than not, with the perennial exception of Clermont Auvergne, the nearly men get there in the end. Which is why Leinster should be taking nothing for granted despite their impressive 25-match unbeaten run and comfortable 27-5 win against Ulster on Saturday in the Pro14 final, their third successive league title. Rattle and Hum, that old U2 album and film title, perfectly sums up the formidable blue machine right now. Listen to their ever-ambitious senior players and it seems they still haven’t found the absolute domination they are seeking. There are, though, two potentially significant snags. The first is Covid-19 which is removing packed, partisan crowds from the equation and denying Leinster the emotional energy that would otherwise make Dublin on Saturday an even tougher place for Saracens to go. Even if the home side prevail, the semi-final is the following weekend and will not allow Johnny Sexton and co to rest up as they normally would. And the second? The rest of Europe, in their various ways, are increasingly out to get them. It is hard to imagine, for example, a more fired-up bunch right now than Saracens as they prepare to throw themselves headlong at the massed blue wall this weekend. After the self-harming winter Sarries have had, this fixture has shone diamond-bright in their diaries as a chance to show off their true selves. If they can disappear into English Championship exile having reminded everyone of their enduring pedigree, a little of the angst of recent months will melt away. Maybe that was why Owen Farrell crossed the physicality line against Wasps: he was mentally using it as a dress rehearsal for a game from which Sarries will not be taking any semblance of a backward step. The England captain’s suspension, though, will not stop the rest of his teammates from coming out fast and hard. Stuart Lancaster has suggested The Last Dance as a potential Saracens motivational tool and one final Michael Jordan-esque leap from the defending champions, in celebration of the soon-to-retire Brad Barritt, is by no means inconceivable. Even if Leinster survive that examination a few other teams may yet prove trickier to beat than some anticipate. Awaiting them in the semi-final will be either Clermont Auvergne or Racing 92 and the Irish province should definitely beware the latter. Since 2011 the list of the four fly-halves who have won the European Cup reads like a playmaking who’s who – Farrell, Sexton, Jonny Wilkinson and Matt Giteau. There is no reason to suspect this stellar list is a coincidence, which is why the magnificent form of Racing’s Finn Russell should be genuinely be concerning Leinster. The Scottish fly-half was at his irresistible best against Montpellier at the weekend, conjuring tries out of nowhere, and his club have been losing European finalists twice in the past four years. They precisely fit the bill, therefore, of a team who have tasted bitter disappointment and emerged stronger for the experience, their 15-12 defeat against Leinster in the 2018 final another obvious source of motivation. The same applies to Exeter Chiefs, seeking to graduate to the European semi-finals for the first time, at Northampton’s expense. That might make them seem like Euro novices but closer examination of their recent history suggests otherwise. They have just topped the English Premiership regular season for the third year on the trot and missed out on a Champions Cup semi-final by only a point in 2016 in a last-gasp thriller against Wasps. Domestically they have appeared in the past four grand finals, losing three against a club since proven to have cheated the salary cap. To say they are keen to make amends is an understatement. And, finally, there is Toulouse, who host Ulster on Sunday. With their scintillating counterattacking game and rich traditions, the French club are another side transparently on the up. They were not good enough last year to derail Leinster in the semi-finals but Antoine Dupont, Cheslin Kolbe and Romain Ntamack are class acts and have all subsequently grown in confidence. Leinster v Racing 92 and Toulouse v Exeter would make a compelling pair of semi-final match-ups and only a foolhardy Irishman would consider this year’s title to be already in the bag. Eyes on the prize Warren Gatland is back in the northern hemisphere to monitor potential members of his British & Irish Lions tour party to South Africa next year. Travel restrictions associated with the pandemic will prevent him attending the Leinster v Saracens match this weekend but he will be based in Europe until December and return in the new year. There is plenty of exciting fresh talent on the fringes of recognition across the four home unions – Jack Willis, Louis Rees-Zammit, Duhan van der Merwe, James Hume – and this autumn is the perfect chance to catch Gatland’s eye. One to watch Historically, home clubs in European quarter-finals have a 76% success rate in 92 matches dating back to 1996-97. Which means that, statistically, one of this year’s four host clubs is set to miss out. My punt, as hinted above, would be Clermont Auvergne, who lost against Racing at the same stage at Stade Marcel Michelin in 2018. But will the absence of spectators for precautionary virus-related reasons make any significant difference? If ever there was a weekend to underline – or disprove – the supposed benefit of playing on familiar home soil, this is it.