City became the richest club in the world overnight when Sheik Mansour took them over two-and-a-half years ago and have since embarked on a spending spree unprecedented in the history of the game.

That investment will begin to pay off if City win next month's FA Cup final, which they reached after beating arch-rivals Manchester United at Wembley yesterday.

But it has also fostered resentment among supporters of other clubs, something manager Mancini insists is unjustified.

Pointing out Chelsea and United had also paid huge transfer fees in pursuit of success, Mancini argued there was more negativity towards City's spending.

He added: "Many times I've been asked about our spending but we didn't buy Cristiano Ronaldo, (Lionel) Messi. We bought young players, good players."

Mancini, who spent around £125million last summer alone, added: "All these players need to improve because it's the first year they're playing in the Barclays Premier League.

"If I'm not mistaken, many years ago when fantastic players came to England, like (Eric) Cantona, at the start it was difficult."

Of City's starting XI yesterday, only goalkeeper Joe Hart had been at the club for more than three years, while several had been signed in the last 15 months.

But with vast sums of money at stake, Mancini has been under pressure to bring instant success to Eastlands, with Champions League football next season the minimum requirement.

The Italian is adamant City will finish in the top four and reiterated his claim winning the FA Cup could inspire a Premier League title push next term.

But he added: "The manager, I think, needs time because, in one year, you can't build a strong team.

"It's important that you improve every week."

City certainly did that yesterday after their embarrassing Premier League defeat at Liverpool five days earlier.

They also cleared a huge psychological hurdle, having not reached a cup final for 30 years and doing so with a victory over their fiercest rivals.

Mancini said: "Our mentality will be more strong because we beat United - and United played with their best team.

"(They were) without (Wayne) Rooney, but we played without (Carlos) Tevez.

"You can win against them only if you play very strong, you play very concentrated.

"If not, it's a difficult day. They win because they have more experience.

"But now, if we work, we can arrive very, very close to them."

He added: "The final will be harder because probably we will go in the final and we are favourite.

"In 90 minutes, anything can happen. If we play with the same spirit, we can win. If not, we don't win."

United fans have a banner at Old Trafford which is updated every year City go without winning a trophy.

It recently ticked around to 35 years and Mancini said: "They can take off this banner.

"We hope we can take it off this year."