While the Brazilian has gone on to shine at Liverpool and now in the future at Barcelona it is a reminder of some of the talent Inter have let slip through their fingers of late.
Familiar malaise and regret for Inter Milan highlighted by Coutinho's Barcelona move
When Philippe Coutinho makes his debut as the second most expensive footballer in history for Barcelona, look out for red faces in the blue half of Milan.
Once upon a time, Coutinho belonged to Inter Milan, who had scouted him as a boy, had him committed to a future with the Serie A club from the age of 15 and proudly presented the prodigy as a first-team squad member a few weeks after they had won the 2010 Uefa Champions League.
Inter paid Vasco da Gama around €4 million (Dh17.9m) for Coutinho, which is around one fortieth of what Barcelona will end up paying to Liverpool as a result of the deal that made Coutinho, earlier this month, the most costly arrival ever at Camp Nou.
But the winners in this are not the Italians in the chain. Four years ago, Coutinho joined Liverpool from Inter for a little over €10m.
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The response in the executive offices at Inter - where the governing regime has changed since Coutinho was the 18-year-old hailed as “the future of this club” by the president Massimo Moratti – ought to be a embarrassed ‘Ouch!’ - at an opportunity missed.
They will look back at a failure to keep faith in, and exploit, the talent of an attacking midfielder who now surfs the crest of his sport’s latest hyperinflationary wave.
Except that at Inter, they have got used to shrugging these oversights off with a weary, ‘Oh, dear. There goes another one.’
Inter’s notoriety for transfer-market misjudgement is one of football’s enduring certainties. Since the Bosman law altered the marketplace in the mid-1990s, the procession of players who have left Inter feeling the club’s indifference towards them is stella.
It goes from Dennis Bergkamp and Matthias Sammer through Roberto Carlos and Andrea Pirlo to Leo Bonucci and now Coutinho. And then there was Clarence Seedorf, who won European Cups with Ajax and Real Madrid, but not with Inter, who swapped him with their neighbours for the long-forgotten full-back Francesco Coco.
Seedorf went to win two more Uefa Champions League titles in the red and black of the smirking beneficiaries of that deal, AC Milan.
All of which might regarded as a warning to Rafinha, the Brazilian midfielder whom Inter are currently chasing, hopeful that Barcelona, Rafinha’s employers, will make him available now that Coutinho will be making midfield spots at Camp Nou even harder to gain and knowing that big-spending Barca have a budget to balance.
Around $35m, with a permanent arrangement possibly preceded by a six-month loan, could make Rafinha an Inter player this month.
Inter are certainly in need of some fresh impetus, as the Serie A season resumes after its winter break this weekend.
Inter topped the table for the first two weeks of December, but a run of seven games without a win, across competitions, since has led to familiar bouts of soul-searching in an institution liable to brittleness.
Lose, or draw, at home to Roma on Sunday in their latest league game and they could slip out of the top three.
This being Inter, the slump has been accompanied by the glimpse on a distant horizon of former Inter players rejuvenated: not just a beaming Coutinho, but recent travellers through the revolving door
The midfielders Gary Medel and Ever Benega, sold in the summer, helped Besiktas and Sevilla respectively into the knockout stages of the Champions League, a competition Inter have not featured in for nearly six years now.
Meanwhile, Geoffrey Kondogbia, loaned out in August, two seasons after Inter made the 24-year-old Frenchman their costliest signing this century, thrives with high-flying Valencia.
Rafinha beware: Inter have particularly careless habits with talented young midfielders. Joao Mario, 25 is the latest to feel restless and underappreciated, 18 months after Inter paid Sporting Lisbon more than €40m for him.
Head coach Luciano Spalletti, who left Roma for Inter seven months ago, may let Joao Mario go on loan somewhere this month. And he wants reinforcements, and apart from Rafinha, is interested in hauling Ramires, formerly of Chelsea, out of Chinese league football.
He has already welcomed in the Argentine defender Lisandro Lopez, on loan from Benfica.
As Spalletti put it, rather colourfully, that addition to an injury-hit back line looked overdue.
“Even my mother could see we needed a new central defender,” said Spalletti, “and my mother is 80”.