The Nerazzurri had won three Scudetti in a row under Roberto Mancini, but he was replaced by Jose Mourinho with the intention of conquering Europe.
The Portuguese fell short in his first season, losing to Manchester United in the Last 16.
Despite retaining Serie A, it was clear that only a Champions League triumph would ensure than Mourinho’s spell at San Siro was seen as a success, and he achieved it in emphatic fashion.
No Italian side had ever managed to win the Scudetto, the Coppa Italia and the European Cup in the same season.
First came the cup win, with the Beneamata beating Roma 1-0 thanks to a 39th-minute goal from Diego Milito.
The title race went down to the final day, but a nervy 1-0 win at Siena, with another Milito goal, made it five-in-a-row.
Then came the big one, the Champions League final at the Estadio Bernabeu.
Inter had reached the showpiece game with a heroic aggregate victory over Barcelona in the semis, Mourinho describing their “dream” as purer than Barça’s “obsession” with winning at the home of Real Madrid.
The opponents in the final were Louis van Gaal’s Bayern Munich, who had also secured a domestic double. The Treble would be won in Madrid, whatever happened.
Mourinho, as he so often does in finals, opted to set his side up to counter-attack; allowing Bayern possession without letting them breach the defensive wall.
With 35 minutes played, a long punt forward by goalkeeper Julio Cesar found Milito, who headed it on to Wesley Sneijder.
The Dutchman delayed just long enough for the striker to dart into the channel, before sliding through a perfectly weighted pass.
Milito made no mistake, firing the ball high past Hans-Jorg Butt and wheeling away in ecstasy.
Then in the second half Milito struck again. A heroic Walter Samuel block denied Ivica Olic, and the ball eventually found its way to Samuel Eto’o in midfield.
The Cameroonian slipped it wide to Milito, who bamboozled Daniel van Buyten and curled the ball into the far corner. Game over.
It was a stunning, unprecedented triumph and one which so far no-one has been able to match, though Juventus will have the chance in Cardiff on June 3.