City start the weekend level on points with Manchester United but remain at the top of the table due to a superior goal difference.
Yet Mancini's expensively assembled side, which has set the pace for most of the season, could start 2012 in second spot as City do not play Sunderland until New Year's Day -- 24 hours after United host bottom-placed Blackburn.
It is so tight that Mancini believes the title race will not be decided until the last day of the season on May 13.
City's Italian manager says he has not set a points target for his side to win the league as the blistering starts from City, United, and Tottenham Hotspur make it difficult to predict how many points will be needed to be crowned champions.
"In this moment City, United and Tottenham have a lot of points compared to other years," said Mancini
"If you said how many points you need to win the league, it is very difficult. I think you need to wait another six or eight games."
City have seen a five-point cushion at the top disappear since the start of December after suffering their first loss of the season at Chelsea and dropping two more points against West Brom on Boxing Day.
But Mancini dismissed suggestions his players are feeling the pressure.
"We knew before West Brom it would be impossible to stay on the top (all the time) or to win the title in January," he added.
"When you play against United, Tottenham or Chelsea, this is impossible.
"We have taken 45 points and scored a lot of goals. We should fight until the end and I think this championship will be decided in the last three or four games."
City have no fresh injury worries although Owen Hargreaves remains sidelined with a knee problem.
Matt Kilgallon is set to answer Martin O'Neill's emergency call - 19 months after his last game for Sunderland.
O'Neill is ready to bring the Black Cats centre-back in from the cold in an attempt to help shackle City.
The Sunderland manager is wrestling with an injury crisis, with Titus Bramble, Michael Turner and Phil Bardsley all sidelined.
The Northern Irishman is set to turn to Kilgallon, who was frozen out by previous manager Steve Bruce soon after sealing a £1.75m ($2.7m) move from Sheffield United just under two years ago.
Kilgallon -- who established a good reputation when he started out at Leeds United -- has been farmed out on loan to Middlesbrough and Doncaster, with the last of just six Sunderland starts coming in May 2010.
The 27-year-old has yet to play any first team football this season, but with stand-in left-back Kieran Richardson also doubtful through illness, O'Neill admits he's short on defensive options.
"The absences are a major blow because we haven't got the largest squad to choose from, so it's a major concern," said O'Neill.
"Matt Kilgallon and a number of other players who haven't played might find themselves playing.
"I'm hoping he (Kilgallon) might get a chance. If he does, hopefully he'll play well. He'll be up for the challenge like the rest of them."
Despite earning seven points from his four games in charge, O'Neill insists Sunderland still aren't out of danger in their bid to climb away from the relegation zone.
"My aim is to get us out of bother. We're still in a spot of bother, it's a real dogfight."
Source: AFP
Source: AFP