The slide rule maths needed to compute the best three runners-up, who also qualify for the quarter-finals, ensure that while the natural dynamic of a big competition getting to the sharp end of business is compelling, other permutations begin to kick in.
This season promises to be no different with the playing field seeming particularly level. Only reigning champions Saracens have really distanced themselves from the pack with their quality and consistency but Clermont, Leinster and Glasgow are all hard on their heels and something good is stirring in Munster again. The tournament is shaping up nicely.
In most eyes Saracens, already the only unbeaten team, have been the stand-outs. This is a club and team that have grown steadily from Euro also-rans to doughty knock-out fighters, to losing finalists and, last year, outright winners. It’s been a long haul with much more failure than success and now is the time to cash in.
Over the last two seasons they have become the new European aristocracy and if they can win at Parc y Scarlets next Sunday they will set an all-time European record of 14 straight wins in the tournament, easing ahead of Munster’s run between 2005-7 which incorporated their first title in 2006.
That run is statistical confirmation of what we can see with our own eyes, the full maturing of an exceptional team who finally came to terms with the demands of Europe, most notably winning on the road which is always what separates the wheat from the chaff.
The 13-match streak includes notable triumphs at fortress-type venues at Toulon, Toulouse and Ulster – as well as efficient jobs of work at the likes of Oyonnax and Sale – where the possibility of any historic home losses by those sides was strangled out at birth. It also, of course, takes in last season’s victory in the final over Racing in Lyon.
Mind you, the trip to Wales next week – minus the injured Vunipola brothers and possibly other big names – could be tricky. Scarlets had their moments in the first game at Allianz Park and backed that up in their last home tie with a win over Toulon.
The trip west has banana skin written all over it yet this Saracens team have proved adept at scrapping for the win pure and simple when the result is everything and the quality of performance is, perhaps, not quite so important.
Clermont, meanwhile, look the pick of the French and seem very motivated as befits a powerhouse, ambitious club still seeking the Holy Grail of European rugby. It was possibly a surprise to see them lose that cracker at Ulster 39-32, one of the best modern-day pool games, a riot of high quality attacking rugby.
The wheels can still come off the Michelin men, or at least wobble, but they would have to mess up spectacularly from here not to claim a home quarter-final.
On the subject of France and French teams, it has been very noticeable in recent seasons that unless you are Toulon, with all their player resources, they find it extremely difficult to win the T14 one year and then bat on and shine in Europe the next.
Racing 92 have never really got out of first gear this season; Stade Francais did reach the quarter-finals last year before being trounced at Welford Road by Tigers in the quarter-finals but Castres (2014), Toulouse (in 2012 and 2013) and even Clermont (2011) have all spluttered badly in Europe the season after that mighty all-consuming effort needed to get across the line first in the T14.
Even the mightiest cash-rich French teams struggle to fight on both fronts and, with the gap in budgets and salaries steadily decreasing, with Premiership sides at least, that trend will probably continue.
Apart from Clermont, the European Champions Cup is on a knife edge for the French. It really is touch and go for Toulouse, Toulon and Montpellier.
The Irish challenge has also reached a pivotal stage. Leinster have given every indication of progressing smoothly although there is still work to do at home to Montpellier next week. A win at the RDS would slam the door shut on the muscular French outfit and although defeat wouldn’t be a complete disaster it would certainly put them in danger of missing out on a home quarter-final.
We’ve come to expect attacking fireworks from Leinster over the years and this current squad can score from everywhere but the most impressive aspect of their recent revival has been their defence where it is possible to see the immediate impact of Stuart Lancaster on his arrival.
Connacht are locked into a three-way tie at the top of Pool 2 which is going to end in tears for either them, Wasps or Toulouse while Ulster need to rediscover their best form in a hurry and win their final two matches if they are to stand any chance. Not impossible but very much a long shot. Glasgow are the other team to catch the eye so far, their only defeat coming against Munster the day after Anthony Foley’s funeral – which Gregor Townsend and some of his team attended.
On that emotional Thomond Park day the truth is that no side in Europe were going to beat Munster – the early dismissal of Keith Earls didn’t remotely derail them – but, that exceptional match apart, the Warriors have been in quite outstanding form, routing Leicester at home and achieving a notable double over Racing.
Stuart Hogg has starred but all sorts of players across the park have been showcasing their skills with the Warriors modus operandi being not far short of total rugby. The only downside is that the waves they are causing could soon see the big French clubs come in with offers that are too good to turn down.
Head coach Gregor Townsend, who will be with Scotland from June onwards, is resigned to Glasgow losing some players, but is not enamoured with the aggressive recuriting of some European giants.
“If clubs are speaking to our players when they have still got 18 months of contract left it is not right and World Rugby has to do something about it. Before, there was much more understanding, comprehension and morality in terms of not speaking to players until they got to the last year of their contract.”