Pep Guardiola's arrival at Manchester City is no guarantee of success, chief executive Ferran Soriano has said.
Guardiola was presented to the City fans at an event on Sunday, taking part in a question-and-answer session as he begins his three-year contract at the Etihad Stadium.
The former Barcelona and Bayern Munich coach has enjoyed great success in his career in the dugout, winning La Liga and the Bundesliga three times while twice lifting the Champions League, Copa del Rey and DFB-Pokal trophies.
But Soriano told Sky Sports News: "The Premier League is the most competitive league in the world by far, so it's a challenge in itself.
"We think we have the platform here for everybody to succeed but it's going to be extremely difficult. Nobody is thinking we are going to win the competition or all the games - not at all. We know it's very challenging.
"We think we have the ingredients but we'll have to work very hard - harder than last year. We are very happy to have the facilities, but this is not even half of the way, this is only the hardware.
"We need the software. We need the talent, the way we play football, the intensity in the games, the hard work - this is the difficult part.
"Our objective is to get to the end of the season with chances to win everything. All competitions are important to us. We know that if we are in the final of the Champions League five years in a row, one year we will win it."