The captain and central defender is out of action since late January due to a calf injury but Mancini is hopeful the player is not far from his return.
London: For all the millions splashed out by Manchester City's Abu Dhabi owners on attacking talents, it is the English champions' grit in defence that is keeping them in the Premier League title hunt. City are 12 points behind neighbours Manchester United after Monday's 1-0 win away at Aston Villa and will in all probability lose their crown as English champions given the league leaders' present form.
However, they will not go down without a fight and nine clean sheets in 11 fixtures so far this year, despite the absence of captain and central defender Vincent Kompany since late January, has kept manager Roberto Mancini in a positive mood.
"We don't have Vinnie at the moment and he's very important to us but Matija (Nastasic) is playing very, very well at the moment," Mancini said of Serbian defender Nastasic. "We had three or four games like QPR, West Ham, Chelsea where we deserved to win and missed chances to score but sometimes it's enough to win 1-0 like tonight and to fight for every ball," he told the club's website.
The City manager said Kompany was in line for a return in the FA Cup quarter-final against second-tier Barnsley at the weekend or the March 16 league clash with Everton, though there was bad news when Jack Rodwell limped off against Villa. "Jack is very unlucky because he was playing really well, it looks like he will be out for another three or four weeks," said Mancini.
With 10 games to go it will take a remarkable turnaround for City to retain their title but Mancini, whose side were eight points behind United with six games remaining last season, knows better than to concede defeat too early.
"We must keep on winning and you never know, this is football," said the Italian. "We know it will be difficult but we must try - we hope that they (United) can lose a point or two before the derby, that would be better for us."
City and United meet in the Premier League on April 8 after which the current pacesetters must play Arsenal and fourth-placed Chelsea.
Will Kompany's return boost Manchester City's title defence?