Carlos Tevez and Emmanuel Adebayor scored twice in the 5-1 victory against Birmingham at Eastlands, with Nedum Onuoha also on target.

City go into the derby in good heart after cementing fourth place in the table - Liverpool could only draw with Fulham today - which brings the reward of a Champions League place.

On the prospect of facing United, Mancini said: "I think it is impossible to continue scoring three or four goals in the next game.

"We will try, but if we win 1-0 I will be happy.

"If we have 1-0 victories in the next five games that will be good for us. Of course we have respect for United but we want to win this game as it is an important one for us.

"First of all though, we have to recover from this game as we have used up a lot of energy."

Tevez made the breakthrough the 38th minute when he scored from the penalty spot after Scott Dann was adjudged to have bundled over Adebayor.

City went 2-0 ahead in the 40th minute when Onuoha was left unmarked as Adam Johnson swung in a corner. The full-back's downward header was touched on by Tevez for his 28th goal of the season and his 20th in the last 18 league games.

Onuoha was originally credited with the goal but said: "He (Tevez) can have it, it's fine. He rushed to me at half-time as he's desperate to be top scorer."

Birmingham pulled a goal back two minutes later with Cameron Jerome heading home following a cross from James McFadden.

City responded immediately with Adebayor scoring in the 43rd minute and they went further ahead in the 74th minute with Onouha shrugging off a couple of half-hearted challenges before scoring.

Adebayor secured his brace two minutes from time after running from deep.

Mancini, who hopes Patrick Vieira can recover from a knee problem in time for the derby, added: "We changed the tempo after 20 minutes and scored three goals before half-time.

"Carlos and Emmanuel are two fantastic strikers and if they continue to play like this afternoon our chances of fourth place will be better."

Birmingham have now failed to win in six league games and manager Alex McLeish said: "It was a strange game, but when top clubs click they can do that to you.

"We defended badly in some situations, especially the goals in the second half.

"But we have the capacity to bounce back. We have shown it in the past many times.

"I will call it a blip and challenge the players to win the next game against Hull."