At every World Cup Fifa pulls together a group of famous old coaches and tasks them with watching all the matches and reporting on trends and tactics. The 2018 finals in Russia have been no exception.
This assembly of the great and good, including Brazil's Carlos Alberto Parreira, Dutchman Marco van Basten, Nigeria's Emmanuel Amunike, Scotland's Andy Roxburgh and man of the world Bora Milutinovic, have told the media they are all agreed on the essential qualities. But they missed one - and it's the one with which Croatia have reached their first World Cup final.
Van Basten and Co. pontificated about the essential need for development, structure, organisation and talent. But the one quality no one mentioned was the one that provides Croatia with their defining ingredient: willpower or character.
Here a minor historical reconstruction is necessary. Croatia emerged as a properly independent nation only at the start of the 1990s after the fragmentation of Yugoslavia, a traditionally prolific production line of fine footballers.
Quickly they made an impact. They reached the quarterfinals of the 1996 European Championship and stormed to third place at the 1998 World Cup in France. The key players included Zvonimir Boban, Davor Suker and Robert Prosinecki, who had all been World Youth champions with the former Yugoslavia in 1987.
Suker, now president of Croatia's national association, scored six goals in France to win the golden boot as the tournament's leading scorer.
Since then Croatia have been regular contenders in both the World Cup and the European Championship, missing out only once on each finals tournament. In the 2018 qualifiers, a team guided by the playmaking stars of Real Madrid and Barcelona - Luka Modric and Ivan Rakitic - finished group runners-up to Iceland and defeated Greece in the playoffs to reach Russia.
Here at the finals they have beaten Nigeria 2-0, humiliated Lionel Messi's Argentina 3-0 and overturned their qualifying conquerors Iceland 2-1. Since then it's been physically fearsome, nerve-shredding stuff. Croatia outfought both Denmark and Russia on penalties and needed extra-time again to battle England to a standstill in Wednesday's semi-final.
The physical and mental strength that wiry little Modric and his team-mates displayed against England defied logic.
They went a goal down in four minutes and were rattled. Their defence shook, their passes flew astray, they mistimed their tackles. And yet... instead of subsiding, the Croats grew stronger.
The greater the adversity, the greater the spirit of resistance. Not only Modric and Rakitic, every man fought as if his life depended on it - from goalkeeper Danijel Subasic and centre backs Dejan Lovren and Domagoj Vida to key forwards Mario Mandzukic and Ivan Perisic.
The longer the game ran on, the greater the influence of captain Modric, who knows both sides of the sweat-and-glory game from his Champions League triumphs with Real Madrid. Win or lose against France in the final, Modric deserves the Golden Ball as the best player in the finals.
Croatia is a nation of only 4 million - but a nation forged in the vicious, bitter, bloody civil war that wrenched Yugoslavia apart in the early 1990s. Nothing has come easy. Several of their players, like French-raised Perisic for example, were brought up abroad after their families fled the fighting.
Not for them the easy adoption of a new nationality. Croat loyalty is not only a matter of pride but a core of the cultural ferocity expressed by their mass of passionate fans.
Coach Zlatko Dalic offered an insight into this mentality in the early morning hours after the victory over England.
"In extra-time," said Dalic, "I wanted to make substitutions but no one wanted to be substituted. Some players played with minor injuries with which they could not have played other games.
"Two players played with 'half a leg' but it didn't show. No one wanted to give in or say: 'I'm not ready.' This shows our character. This is our mantra: 'Nobody give in; never give up'.
"Before this World Cup I said the tournament would be won by a team with character. See how the big powers - Brazil, Argentina, Germany, Spain - have already gone home. But we were 1-0 down in three games in a row against Denmark, Russia and England, and we overturned all these matches.
"We are a nation of people who never give in. We are the ones who have character."
Thus the quality the experts - and France, in particular - may ignore at their peril.
