When the Argentine centre-back joined Everton from River Plate I did not think he stood any chance of success. I felt that in the Premier League he would be exposed for lack of quality, pace and physicality.

True, his first couple of months have not been unblemished. He is unlikely ever to be a candidate for a world XI. But he appears to have settled in well, exuding confidence right from the off. Clearly, he is considerably better than I had thought.

This, of course, is something to be celebrated. Far better that players exceed your expectations than the other way round.

I don’t feel any particular shame about missing the target. These things are not a mathematical exercise. A player moving continents, stepping up in level – there are so many imponderables that moves of this type will always be a gamble.

By way of example, Funes Mori’s Toffees coach, Roberto Martinez, made an earlier foray into the Argentine market when he was in charge of Wigan, buying Estudiantes striker Mauro Boselli - a player I advised another Premier League manager against. Boselli, Wigan’s record signing, did not manage a single EPL goal, and his failure was a factor in the club’s relegation.

I do not cite this to be sneaky or to compare myself in any way to Martinez, who has forgotten more about football than I’ll ever know. It is merely to illustrate the point that no one gets it right all the time.

Mistakes, though, are always an opportunity to learn. So why was I wrong about Funes Mori? Perhaps the roots lie in an earlier mistake.

Some Celtic supporters have not forgiven me for thinking that Brazilian centre-back Rafael Scheidt would be a success in Scotland more than 15 years ago. True, he was unlucky with injuries but the plain truth was that he was simply not up to the job – despite doing well in domestic Brazilian football and for the national team.

When he performed with credit in a high-risk international that Brazil played against Barcelona in 1999, I had no hesitation in singing his praises.

I had forgotten the collective context. Playing for Gremio, or Brazil, he could position himself deep, so that anything behind him went through to the keeper. And, a constructive figure, he had space to catch the eye with his two-footed passing out of defence.

In British football, though, he was asked to operate much higher up the field, where his lack of pace was badly exposed. Events around him on the pitch were taking place quicker than he was used to, and, initially at least, there was the problem of language – because defending is always a collective undertaking.

The failure of Scheidt gave me a road map for other centre-backs coming straight in from South America. When Argentina’s Gabriel Paletta joined Liverpool in 2006 I argued that this was a case of a promising player moving too soon – vindicated when he failed in England only later to do so well in Serie A that he became an Italy international.

Fellow Argentine Santiago Vergini at Sunderland, Brazil’s Bruno Uvini at Tottenham (swiftly deemed sub-standard even in the reserves) and Argentina’s Federico Fazio at the same club – all were moves I was right to be sceptical about.

The firm conclusion (and I am aware that Fazio came in from Spain) – it is extremely hard for a centre-back to move straight from South America to England.

I did know that Funes Mori counted on a considerable advantage. His family moved to Texas when the Argentine economy imploded in 2001. Language, such an important asset for a defender, was not going to be a problem. Even so, I never expected him to buck the trend.

After he made such a confident start, some Everton fans were screaming the accusation that I had never seen him play before. If anything, the opposite is true. I had watched too much of him and had not adjusted my opinion to make allowances for his progress.

Ramiro Funes Mori is a late developer. As Argentina coach Gerardo Martino said recently, he “was a player who no one rated.”

Ramiro was ‘the other one’, the plodding defender in the shadow of his much more glamorous twin brother, centre forward Rogelio Funes Mori.

It was Rogelio who won a reality TV show in the US with a prize of a few training sessions at Chelsea – which ended up getting him, and by association his brother, onto River Plate’s radar. Rogelio was the first-team regular, the Under-20 international, the one sold to Europe (Benfica, where he failed to make much of an impression and has subsequently moved to Mexico).

In that strange dynamic that twins can have, perhaps Ramiro needed Rogelio to move away in order to blossom. And after his brother’s move to Portugal came another important event – a change of coach at River Plate.

Ramon Diaz had seemed reluctant to let Ramiro anywhere near the first team, at either left-back or centre-back. New man Marcelo Gallardo clearly thought different, and the injuries to Colombian defender Eder Alvarez Balanta presented an opportunity.

Under Gallardo, River accumulated titles and the press hailed Ramiro Funes Mori as the new defensive strongman. I was highly sceptical.

I have seen many examples in recent years of both Brazilian and Argentine domestic football taking on airs of self-delusion. Understandably, it is hard for them to acknowledge how far the standard of their club game has fallen in the globalised era.

A frequent self-defence mechanism is to proclaim any player who puts together a sequence of solid games as some kind of phenomenon. It was not going to fool me! Perhaps, subconsciously, I was a little jaded by being exposed to an excess of mediocre South American club football, and I took this feeling out on one of the players.

So when I watched Funes Mori I was blind to his improvement. I only saw the bad side because that is all I was looking for.

I nodded sagely at his mistakes. They confirmed my pre-conceived view that had been formed in different circumstances, when he was still finding his feet and playing for a coach who was clearly not his biggest fan.

Every time he was beaten for pace, played a poor pass out of defence or went to ground to tackle, I chalked it up as a moment that was representative of the player, while ignoring all the good things he was doing. Because it lacked the flexibility to take account of his development, my evaluation of him was unfair, and, as it has proved, unwise.