Manchester City manager Roberto Mancini believes his team's commanding 4-0 FA Cup victory over Leeds could be the springboard for an unlikely onslaught on leader Manchester United at the top of the Premier League.

City currently trails its cross-city neighbor by 12 points, with speculation mounting over Mancini's future given its current indifferent form.

Mancini, who ended City's 35-year wait for silverware when he led it to the 2011 FA Cup, would do his chances of holding onto the job a power of good were he to lead the team to success in this season's tournament.

But the Italian insisted that if his side performs as it did in advancing to the quarterfinals of the FA Cup, it can overhaul United in the league.

"In Italy, you say a game like this is like brodino soup, a starter," said Mancini. "I hope it can help us to start to win in the Premier League.

"I am happy because it was important to win after losing to Southampton. If you score two goals in the first 20 minutes it's easier, but you know the FA Cup is a difficult competition and Arsenal yesterday, Everton, other teams who play in the Premier League, are out of this competition.

"Every team plays like it is the Champions League final. You should play 100 percent if you want to win.

"If you don't play with concentration, it's difficult. We started well with great intensity. We were concentrating on this target. After we scored four goals, the performance was important."

City's supporters certainly still back Mancini with the Italian's name ringing out around the Etihad Stadium during a game which very quickly headed towards a rout.

Two goals from Sergio Aguero, the first a disputed penalty after 14 minutes which followed Yaya Toure's early opening goal, were the highlights of a game which also featured a goal from Carlos Tevez soon after the restart.

"Yes, I am happy for this," said Mancini, when asked about the supporters' backing for him. "For us, they are really important and when we lose a game, like against Southampton, then we want to try to win because they deserve to win every game."

He also said: "I hope Sergio will be like this from now until the end. If our strikers continue to score from now until the end, the championship is not finished."