City have never been to this stage of the competition before after two disappointing group stage exits under previous boss Roberto Mancini, and now face one of their biggest tests since the side came in to Sheikh Mansour's millions.
Pellegrini, who has never led a team to victory over Barcelona despite managing Villarreal, Real Madrid and Malaga in La Liga, will almost certainly be hoping to take advantage of a questionable Barca defence by rolling out his vaunted attack featuring Spanish stars Jesus Navas, David Silva and Alvaro Negredo, who will be looking to put one over their international team mates.
But whilst they must use their flair in the final third in order to gain an advantage, they must also be wary of the obvious threat posed by Lionel Messi, despite some saying that he doesn't perform against English clubs.
The key will be to try and operate with a holding midfielder who can stick with Messi throughout the game - just like John Obi Mikel has been used for Chelsea in their recent success , and the return of Fernandinho will serve as a boost to Pellegrini, especially after the failed experiment in midfield against Chelsea.
Pellegrini chose to push centre back Martin Demichelis forward from centre back into midfield to nullify the threat of Blues playmaker Eden Hazard, but the Argentine international was simply too slow to contain Hazard, and not technically good enough to work as a link between the defence and midfield.
But Fernandinho's impending return to the City line up will almost certainly prevent Demichelis from featuring in midfield again tomorrow night, and the box-to-box nature of the Brazilian combined with Yaya Toure in the heart of the City midfield will help Pellegrini's side be effective going forward and defensively, though having a true holding midfielder to sit in front of the back four would be ideal in a situation like this, which is something the City boss should look at resolving in the summer.
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