Roberto Mancini desperately tries to return the winning mentality to his faltering Manchester City team

Italian changes his tune as he struggles to revive title challenge but public rift with Nasri and Hart piles on the pressure ahead of trip to Newcastle

After the deference and slight duplicity of his public pre-derby talk last weekend, Roberto Mancini took off the gloves and set about the task of holding on to the Premier League title, and his job.

Manchester United can move nine points ahead of their neighbours if they defeat Sunderland today and City lose at Newcastle, and Mancini abandoned that deflection strategy he has of claiming Sir Alex Ferguson’s team are better. His own side is the best one and was superior in the 3-2 defeat at the Etihad Stadium, he said, and the only reason United won that game was because they threw themselves into defending.

“I don’t say they are lucky because United are a strong team,” Mancini said. “When I say they have more experience it is for this reason because they notice [and do something about it] every time they are not better than us. Now they are not better than us but they know they should defend very well – and they defended for all of the second half.”

His argument took a little getting to grips with, but it was one of a manager who knows he must dispense with subtleties and somehow drive his players into a winning mentality. Even as he spoke, City were preparing to slip out news of their £97.9m losses, which amplify that the days of transfer market largesse are gone if they are to comply with Uefa financial fair play rules. Mancini must stick with the squad he has got this winter, barring an injury emergency, though the most searching question is whether he can inject some motivation into some of those players with whom he seems at odds.

Mancini effectively confirmed that there had been a set-to with goalkeeper Joe Hart in the home dressing-room on Sunday and it is understood that a disagreement has taken place this week with Samir Nasri – who, after removing his head from the City wall when Robin van Persie’s winning free-kick was fired in on Sunday, missed training on Wednesday with “a headache”. Mancini’s translator clarified that the Frenchman has had a sinus problem, though it was fairly evident that the relationship has been strained.

How had Nasri been this week, the manager – who says there is a two per cent chance of captain Vincent Kompany playing at St James’ Park today – was asked. “I think Samir knows this but there is no problem,” he replied. “Everyone can do a mistake. It’s impossible to be perfect.”

The last part was true, though the past 18 months have not worked out as Mancini would have hoped for the first player whose signature City beat United to, and the public playing-out of the free-kick embarrassment comes at a difficult period for the 25-year-old.

His personal reputation has been damaged in France by the revelation in the tell-all autobiography of former national coach Raymond Domenech that Lilian Thuram thought Nasri was “trouble”. That played heavily in the French media, at a time when Nasri finds himself ostracised from Didier Deschamps’s side – initially suspended for three games for his bizarre outburst at a journalist at this summer’s European Championships, and unable since to get his place back. He severely tested Mancini’s patience during the September international break when, after the manager had allowed his senior players time off, Nasri took off to Las Vegas’s Bellagio casino. It did not help that he sustained a hamstring tear against Real Madrid in his first game back.

Nasri is a strong character. Someone who is close to him observes that his outlook is that “what doesn’t kill you makes you stronger”. Mancini trusts him, always plays him in the big games and rarely keeps him on the bench. But Nasri is a prime example of one of those players who is not changing games as City expected when investing £24m on him.

Hart is at the core of the City collective, which makes Mancini’s public prickliness towards him puzzling. The manager yesterday did not deny the dressing-room rumpus with Hart, Nasri and Carlos Tevez, reported on these pages on Tuesday. “I used to keep it in the dressing-room – not like other people that talk outside the dressing-room,” Mancini said. “For me it’s not like this and we know where this comes from.”

Tevez will not be happy with the public criticism either and even those who do not deviate from the positive script, such as David Silva, raise the question of how they can be driven to last season’s heights. Silva admitted this week that his troublesome left ankle requires “constant care.” The prospects of Mario Balotelli being a consistently dangerous force are fading by the week, though the one-on-one coaching for him at Carrington on Wednesday demonstrated that Mancini has not given up.

Ferguson is expected to have Nemanja Vidic back against Sunderland – the side United played on the afternoon City so dramatically took the title in May. He could reflect with equanimity on Mancini’s claims that United didn’t touch the ball for 20 minutes on Sunday. “I don’t think that’s accurate but it doesn’t matter,” Ferguson said. “We’ve all got opinions on how you win a game or lose a game or whatever. There are a lot of big games to come and six points isn’t such a healthy lead. But I’m happy with it and it’s their challenge to try to catch us.” Game on.

Next five matches for Manchester clubs

* Manchester United

Today Sunderland (h)

23 Dec Swansea (a)

26 Dec Newcastle (h)

29 Dec WBA (h)

1 Jan Wigan (a)

* Manchester City

Today Newcastle (a)

22 Dec Reading (h)

26 Dec Sunderland (a)

29 Dec Norwich (a)

1 Jan Stoke (h)