Sergio Aguero turns to his young son Benjamin and cracks a joke that only the Spanish-speaking members of his entourage and our interpreter can appreciate at first.

So just how angry was Manuel Pellegrini after Manchester City’s shocking Champions League defeat at home to CSKA Moscow in midweek?

‘Even little Benjamin was angry,’ says Aguero, turning to the five-year-old who sits adoringly by his side. ‘And he told me I dived to try and win a penalty!’

Sergio Aguero continued his rich vein of form by scoring the winner in Manchester derby

But the striker could not prevent Man City slipping to Champions League defeat in midweek

It is less than 24 hours after City’s flagging European campaign sank to a new low and Aguero is putting on a brave face. Pellegrini’s team can still qualify for the knockout stage despite languishing bottom of Group E without a win from four games. And the man who will for ever be remembered for firing City to their first Premier League title in the most dramatic way imaginable is not giving up.

For those supporters who might not be feeling so optimistic, Aguero has this message in response to the suggestion that he might be forced to go elsewhere in search of Champions League glory.

‘Not only will I stay the four years to make it eight here in total,’ says Aguero, who signed a new contract in August, ‘I’ll stay beyond that — until we win it.’

In the meantime, City fight on despite lengthening odds and growing criticism. They have lost three of their last four games in all competitions. Talk of Pellegrini carrying the can is dismissed with a polite smile, however.

‘It’s easy for everyone to suddenly decide it’s the man at the helm who is to blame, but I would say in situations like this, when we haven’t played well as a group, we are all in it together,’ says Aguero.

Sergio Aguero raises a smile with store staff at his book signing session at the Etihad Stadium on Thursday

‘The Champions League group table is not what we would have expected. We are not seeing the real City playing in Europe at the moment, but we still have these last two games when we hope the real City will turn up.

‘I guess that if we don’t turn it around, you would consider it to be the worst Champions League campaign the club have had. But I have spent a lot of years in football and am aware that these things can happen, you get bad runs. And I am also aware that you work your way out of those bad runs and come out the other side positively.’

Aguero’s own battle against adversity is documented in his autobiography Born to Rise, from an impoverished upbringing in the slums of Buenos Aires to a place among Argentina’s football royalty as the husband of Diego Maradona’s daughter Giannina (they separated when Benjamin was three).

The events of May 13, 2012 feature prominently, ‘Agueroooooo’ scoring the second of City’s two injury-time goals against Queens Park Rangers to snatch the title from Manchester United and spark scenes of delirium at the Etihad as the hero disappeared beneath a pile of players.

‘You f*****g idiot, I love you big b*****ks,’ is revealed as Mario Balotelli’s contribution to the celebrations.

Aguero signs a copy of his new book for a fan at the Etihad Stadium on Thursday

The iconic photo of Aguero twirling his shirt in the air hangs on his wall at home, and he has kept the boots he wore that day. The memories will return this evening when City face QPR at Loftus Road.

‘Whenever you mention the words “Queens Park Rangers” it always comes to mind,’ says the 26-year-old. ‘That will remain etched on my memory for ever. I’ve watched it back loads and loads of times, as you can imagine.’

It is the most significant of Aguero’s 87 goals in 137 games for City since he joined from Atletico Madrid for £38million in 2011. The latest, a winner in last Sunday’s Manchester derby, makes him the Premier League’s top scorer ahead of Chelsea’s Diego Costa.

No wonder Pellegrini believes the striker is capable of challenging his best friend Lionel Messi and Cristiano Ronaldo for the Ballon d’Or. Aguero, however, accepts that he must match Messi and Ronaldo on the European stage before he can be considered a serious contender.

‘It’s great to be mentioned in the same breath as those players,’ he says. ‘But when you mention Messi and Ronaldo, for me those guys are from another planet in football terms. Maybe I need to put in some good performances in the Champions League in order to be considered seriously to win the Ballon d’Or. If we don’t do well in the next two games and get knocked out, the only way I’m going to win that award is by scoring 70 goals in the Premier League this season.’

Even in these darkest of days, you wouldn’t put anything past Aguero.