Defeat would be disastrous, it would all but end chance of them going through to the knockout stages. It would leave Mancini clutching to his job with a thread, if he isn't already. His antics at West Ham on Saturday, in which he sat on the sideline alone suggests that he's under increasing pressure. His reaction in recent press conferences also shows the increasing stress that's mounting on the Italian. He may have delivered a first League title in 44 years, but failure in the Champions League could prove to be his downfall, like it was a Inter. Mancini and Champions League don't blend.
Ideally for City they could have got an eaiser draw, however it is the Champions League and a group full of 'champions' did seem fitting. Unlike their Dortmund counterparts they've struggled to get a grip on European football, even when they were in the Europa League they weren't the competition's strongest side. A start in the Bernabeu also wasn't ideal, but they did throw it away after leading against a Real side far from top gear at that time. Dortmund at home was a wasted oppourtunity, the away side were unlucky not to win. Although City surely should have been favourites and they never got going, like they never have in European competition.
Ajax were top class last time the two sides met, as they won 3-1. Perhaps, City did make Ajax appear better than they are. This is a side that's not even in the best in the Netherlands at this current point in time, poor defending cost them a 2-0 defeat to Vitesse at the weekend as they languish in 5th.