Roberto Mancini believes that Manchester City's 3-1 victory at Newcastle United has sent a clear message that they will have a major say in the destination of the Premier League title.

City are still six points behind Alex Ferguson's Manchester United, who beat them a week ago, but his players' reaction at St James' Park on Saturday delighted Mancini.

However, there was an unsavoury aftermath to the game when it emerged that Aleksandar Kolarov, the City defender, was the subject of a police investigation.

Kolarov, a Serbian, is believed to have had angry exchanges with a fan who was waving an Albanian flag.

There is a long history of bitter tension between Serbia and Albania over Kosovo which unilaterally declared independence from Serbia in 2008.

A spokesman for Northumbria Police confirmed they had received a report of racist language being used.

He added: "We take such allegations extremely seriously and inquires are ongoing into the incident."

City earned their win over Newcastle through goals from Sergio Aguero, Javi Garcia and Yaya Toure, but it was scant reward for the quality of their performance, particularly in the first half.

"The season is long," said City coach Mancini.

Sir Alex (Ferguson) knows that better than me. He knows this championship is not finished when there are only three games to the end. Now we have 21 games to the end, so it is still open.

"When you have a defeat against anybody, but in particular against United, it is important to win again very quickly -- and we have started here, where I don't think a lot of teams can win. I was very satisfied with the performance."

However, when asked if he had special words for Ferguson in the wake of the win, Mancini said: "The message is only Happy Christmas for December 25th."

City were leading 2-0 early in the second half and should have scored on several other occasions before Demba Ba claimed his 11th goal of the season to give Newcastle hope of avoiding their sixth defeat in seven games.

Mancini said: "I don't understand why we were missing all these chances in the first half. When you have six or eight chances, you need to score more goals.

"If not, it can be like the second half, when they scored their goal. It can change everything, and I was anxious.

"In the second half, Newcastle were better and they pushed into our half, but we had other chances to close out the game."

Mancini did not even include Mario Balotelli among his substitutes and he explained: "He is not in good form at this moment and it is better for him to carry on training and train well. When he is in good form, he will play."

Newcastle are now deep in relegation trouble, but manager Alan Pardew said: "There were a lot of pleasing things, but no points, which is my concern.

"We made a great start to the first half then Manchester City produced what they can -- a 20-minute golden period when they got a goal and could have got another before their second.

"But we bossed it in the second half. Our mentality was strong to come out like that. We had fantastic chances after we scored. This place would have gone mad."