From down at heel to top dogs: How Irish coach McCall has galvanised Munster opponents Saracens
'They seem to find structure in chaos' - Rassie Erasmus
Chaos and structure have mapped the Saracens journey, from a penniless existence on a dog dirt-infested public park to the millionaire's backing that helped them become top dogs of Europe.
Aptly, it took the reigning English and European champions the entire 21 years of professionalism to come of age, and ascend the Everest of their vaulting ambition.
They have no desire now to be budged from their peak.
Now their ambition is to frank their championship status by becoming a multiple winner, just like those teams they once envied - Leicester, Wasps, Toulouse, Toulon, Leinster.
And, of course, Munster.
At their core is an Ulster man, Mark McCall, coursed from his own province by ill will, and a tight-knit squad who emerged through many avalanches before finally negotiating a route towards the pinnacle of European rugby.
Rassie Erasmus, indeed, believes they may now surpass even those levels; he compares them to the best Super Rugby has to serve up; his may be typical Munster underdog blather but the praise is not without foundation.
As a South African and keen student of the game, Erasmus appreciates the history of the peripatetic Londoners who, after years without a true home or a real identity, forged a path to greatness with more than a little help from some contemporaries of the current Munster coach.
With the early backing of local businessman and sometime junior player Nigel Wray, Saracens had tried - and failed - to break the glass ceiling in the 1990s, after a dalliance with glitz, glamour and grunt, from Michael Lynagh to Francois Pienaar, Philippe Sella to Paul Wallace.
They persisted with a cosmopolitan approach - coaches Pienaar, Buck Shelford and Rod Kafer came, and went, quickly; Leicester and Wasps were standard bearers at home and abroad; like the Tommy Cooper fezzes adopted by their fans, 'Sarries' were simply old hat.
They reached a semi-final in 2008 under a wily old friend of Ireland, Alan Gaffney, but were undone by Munster.
Eddie Jones arrived briefly, promising expansive, winning rugby; his elaborate vision was a decade too early for the English game, it seemed.
Saracens did broaden their outlook but they would paradoxically narrow their focus by doing do. Instead of Australia, they sought Springbok inspiration.
CEO Edward Griffiths had helped unite a nation during the 1995 Rugby World Cup; now, backed by billionaire compatriot Johann Rupert, he ushered in the 'Saffercens', as their persistent critics at home and abroad would now dub them.
Nearly 20 players were chucked as irascible coach Brendan Venter attempted another revolution; at this time, the sport was dominated by dull 'kick-and-chase' tactics and nobody was duller than Saracens.
The club were trying to attract London's South African diaspora; instead, they were slowly losing their soul and identity. Saracens could neither buy titles nor achieve them playing turgid, catch-and-kick rugby. The club needed another radical overhaul.
They required style and substance, a club mentality allied to a transformative game-plan, underpinned by a cohort of indigenous players.
Having found that balance, domestic dominance followed but, just like Munster and Leinster before them, they required to learn the harshest of lessons in Europe.
A try-less quarter-final loss in 2012 spawned the change in style, before they lost a final, then another semi-final, all to French sides.
"We changed a lot," admits McCall who joined in 2009 and would develop the new style with Joe Shaw and Kevin Sorrell, "particularly our strength and conditioning, because we found ourselves fighting against people who were more powerful, more offensive, than us. We changed the people, our recruitment, even our philosophy."
"Each campaign and with each year," notes centre Brad Barritt. "Our game-plan has evolved and that has been why the team has stayed successful.
"We have never stood still. There has always been a hunger and desire which is led by Mark. The team is evolving and getting better year in, year out.
"We've always prided ourselves on being a team that can have both a pragmatic way and then now, probably in the last two or three seasons, added a cutting, clinical edge to what we do in attack.
"That has allowed us to pull away from teams when we have them by the scruff of the neck.
"I don't think we have ever concerned ourselves about opinions from outside of our iron dome which we speak about."
Even now, nobody likes them but they don't care.
Last season, they would become the first side to win every game on the road to becoming champions of Europe - the supreme irony being that they reverted to old type in the rain-lashed final to grind their way to victory against Racing 92.
They reached their destination by reminding themselves from where they had come.
"They started out as a team who suffocated and strangled teams out of life and hope and belief during matches," agrees Erasmus.
"Now they've developed into a team that does that but when they're on attack they have these almost rugby league mini-moves which seem to come off, matching that with a great kicking game and great finishers."
This is their fifth semi-final in a row; Munster haven't played in one for three seasons; now Saracens are the standard bearers, where once they were in the shadows of the Irish giants.
"They've been there for six or seven years now," notes Keith Earls. "That's where we want to get back to."
Such has been the swing in fortunes for both these sides since their last semi-final meeting nine years ago.