Roberto Mancini is our 'champion', says Manchester City chief Ferran Soriano in rare public backing

Ferran Soriano breaks cover to praise under-pressure manager and dampen speculation on his exit

The Manchester City chief executive, Ferran Soriano, has made his first public comment on the work of manager Roberto Mancini, declaring that he is "a champion" and that "it is not easy to win back any league, especially the Premier League".

Though some assume that Mancini's failure to keep pace with Manchester United or succeed in Europe means that the Italian's future is contingent on FA Cup success this season, that is not a foregone conclusion. Mancini is close to the club's chairman, Khaldoon al-Mubarak, and the feelings of the low-profile chief executive towards Mancini are actually very unclear.

Soriano was more discursive in an interview with Gazzetta dello Sport about how he feels the reigning Premier League champions need to curb their heavy spending and emulate the transfer policy of his former club Barcelona – who, it should be said, were not averse to making big-money signings to slot in among their home-grown players.

Soriano clearly wants more players coming through the academy, now headed up by the former football director Brian Marwood. "My way of football? One year you can win with luck, but in the long-term you need planning and investments to reach the final of the Champions League," Soriano said. "In 2003, we did a study at Barcelona. For each player delivered to the first team from the cantera [academy] there was an average cost of €2.4m [£2m]. That's nothing if you think of the current costs in the game. Even at the age of five years you should get the style of the club, then the rewards will come.

"Our problem is to find players stronger than the ones we have and that is not easy. There are rumours about players coming to City, but I never comment on transfer market rumours. In the last three years there have been losses of €235m [£199m], then of €118m [£100m] and now there is a 'red line' of €59m [£50] [imposed by Uefa's financial fair-play regime. But we also have just invested €150m [£127m] for the infrastructure of our youth system – [the Etihad Campus]. It's a fantastic project, focusing on financial sustainability."

Manchester United will discover on Friday if Luis Nani will be banned following his dismissal against Real Madrid but Robin van Persie launched a strong attack on referee Cuneyt Cakir. "The worst thing is that Uefa supports him," Van Persie said. "That's cowardly, because I really don't understand it. Why don't they just be honest and say 'he hasn't seen it'? I didn't understand before the game that this man would be the referee, such an unknown referee who hasn't been in charge of a big game for months."