Flamini, who played alongside Fabregas at Arsenal, was full of praise for the Spain star's abilities but has hinted at a possible weakness in the 25-year-old's game which the Rossoneri could look to exploit.
"Fabregas is a player with many qualities, as he has incredible vision and is also very good in front of goal," he told Milan Channel. "As for his defects, at times he 'forgets' to defend."
|STILL KNOWS HOW TO SCORE|
|6.50||Cesc Fabregas is 6.50 with bet365 to open the scoring in Milan v Barcelona|
Barcelona head into the tie as clear favourites to progress, and Flamini conceded he would rather have faced different opponents at this stage in the tournament.
"Barcelona have great individual talents and play wonderful football, so they are among the favourites for the trophy," he continued.
"Admittedly, we would’ve preferred to face a different team at this stage, but they will certainly be two fantastic games. We will do everything possible to surprise Barcelona."