PSG v BaAccording to Unai Emery, the Paris Saint-Germain manager, there are five keys to team spirit.
He lists them in his book on management, Mentalidad Ganador, or Winning Mentality, and calls them his 'Five Cs'. They are, roughly translated from Emery's native Spanish: Commitment, Communication, Confidence in One Another, Counting Up - to specific targets - and Coming Together.
Mostly, Emery’s systems have served him well. He is best known, perhaps, for his shrewd analysis and tactical acumen, but is also a respected leader of men.
He handled a waspish squad and boardroom while in charge of Valencia. He dealt with a high turnover of personnel while at Sevilla, where his line ups may have altered as players were sold and bought, but successive Europa League titles were seized. PSG saw his record of serial achievement in Europe as the best reason for hiring him in the summer of 2016.
Emery’s Five Cs formula is undergoing a stern test at the moment.
There is a problem with one big C, namely Cavani and his relationship with PSG's €222 million (Dh960m) man, the most expensive footballer in history, Neymar. The story will not go away.
Edinson Cavani, Ligue 1’s top marksman last season, and Neymar, whose advisors let it be known that part of his motivation for leaving Barcelona two months ago was to allow his talent to flower out of the shadow of Lionel Messi, very publicly disputed the right to take a penalty 10 days ago against Lyon. They have not played alongside one another since.
PSG denied a report that the club had tried to resolve any recurrence of the issue by offering Cavani a one-off payment of €1m to step down from his role as delegated penalty taker. That is not so much team-spirit management by the theory of the five Cs as team spirit suppressed by the theory of the limitless funds.
What is beyond doubt is that, as the Paris club test their ambitions against Bayern Munich in the Uefa Champions League on Wednesday night, every interaction, every glance and every word shared between Cavani and Neymar – who has, Emery says, recovered from the foot injury which kept him out of Saturday’s 0-0 draw with Montpellier – will be scrutinised via magnifying glass.
A few in Bayern's hierarchy have watched PSG's high-profile internal squabbling with a hint of schadenfreude. Uli Hoeness, the Bayern president, took the opportunity ahead of the fixture to reprise a favourite theme: criticising heavy outside investment in football clubs. PSG's vast spending – apart from the Neymar buyout fee, the club have committed €180m to the purchase of Kylian Mbappe – is funded by their Qatari owners.
"The time will come," Hoeness told Kicker magazine, "that these patrons will say, 'That's enough! We've put in so much money and we haven't achieved what we wanted.' Sporting success cannot be just created in the way they predict".
Hoeness may have been stirring, and he was certainly bypassing all the resemblances between PSG’s business strategy and Bayern’s own.
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Bayern may have held the lease on their penthouse in the top storey of elite football longer than nouveau riche PSG, but they maintain it in much the same way. PSG, pushed back last May into second position in a Ligue 1 they had got used to winning at a canter, promptly went out and hired the teen sensation Mbappe from Monaco, the champions.
Since Bayern were last beaten out of top spot in the Bundesliga by Borussia Dortmund, in 2012, they have made the principle of weakening their nearest rival a trademark. They lured Mario Gotze, then Robert Lewandowski and then Mats Hummels from Dortmund.
And Bayern’s solution to a glass ceiling that has built up for them at the semi-final stage of a European Cup they have won five times in their history? To bring in as manager Carlo Ancelotti, seasoned master of Champions League triumphs. That is the same Ancelotti whom PSG employed when they came into their sudden wealth, to steer them towards the first of their four successive French league titles between 2013 and 2016.
Ancelotti reflected last week he had during his 18 months in Paris “helped organise PSG and change its mentality. PSG grew from there". He left for Real Madrid in the summer Cavani arrived, thus avoiding a territorial jostle about the centre-forward position that was to simmer between Cavani and Zlatan Ibrahimovic.
At PSG, Ancelotti is warmly remembered for a man-management style that cultivated harmony. At Bayern, they appreciate those qualities.
But they also ask, with growing urgency, that their serene Italian manager bring them that overdue European Cup, and expect him to work out how to keep upstarts like PSG in their place.