Goals from Mario Balotelli, Adam Johnson, Vincent Kompany and James Milner gave City a 4-1 home win over Aston Villa on Saturday.

The three points helped them move above city rivals United following their 1-1 draw with Liverpool at Anfield.

The victory came at a perfect time for Mancini's side, who will now go into next Sunday's clash at Old Trafford as league leaders, and the 46-year-old is pleased to be top ahead of the grudge match.

"We've only played eight games and there are 30 to go," he said.

 "We should be happy to go to Old Trafford on the top but we should understand that the championship will be long and that this position can change every week."

"For us, it's important to stay there on the top or very close to the team who is at the top and we'll fight until the end for the title."

"We have started very well and won a lot of games but we need to improve more."

The hosts were impressive against Alex McLeish's men but Mancini, who jokingly booed an announcement from the City press officer stating that no questions could be asked about the Carlos Tevez saga, admitted the Blues started somewhat sluggishly.

"We had a problem in the first 15 minutes because when the players come back from an international break it is always difficult," he said.

"But I think after 15 minutes we played very well, Mario (Balotelli) scored a fantastic goal and I think that changed the game."

"We started the season very well, we knew that this week would be hard because we played Aston Villa and then we play Villarreal which is a crucial game for us and then we have the derby so our mind is very busy."

Balotelli's opener continued his fine form in the absence of both Tevez and Sergio Aguero, and Mancini was full of praise for the Italian youngster.

"I think that Mario is always happy," he continued. "He had four or five matches on the bench but I think he understood. He has played well, he has scored in four games in a row but Mario can change in every moment.

"He's worked well and played well. He's motivated, he's playing, he is scoring and it's an important moment for him."

Meanwhile, Villa boss Alex McLeish is in no doubt that Mancini's men are title contenders.

Speaking after the game, he said: "They've got to be contenders with the squad that they've got, there's absolutely no doubt about that."

"City have obviously changed and rotated their team a little bit today but they can bring in players for which they've paid 20-30 million pounds to replace those guys that are out."

"After a nervy start they got their goal which settled them down and when you go a goal down at these type of clubs it can be very difficult."

It was Villa's first defeat of the season and the Scot agreed that the defending of his charges at the Etihad Stadium was unacceptable.

"We're a team that are in transition, there are a lot of young players in the squad and there's a learning curve there but as I said, I'm disappointed we didn't come away from here with something and I think if we had defended better at corner kicks, I believe we would have," he said.

"If you lose goals like that then you can forget it. Needless to say we'll be on the training ground this week trying to put that right."

"Every other team will be looking at the result and thinking that City must have cut Villa to ribbons but they didn't. It was horrendous defending."