The Senegal right-back, signed initially on loan from Lens until the end of the season, has struggled in his opening two games against Fulham in the FA Cup and Arsenal last weekend.
The Blues chief said: "He’s played at the top level in France and a few weeks ago I saw him play against Bayern Munich in Europe, but it has been difficult for him.
"He must improve quickly. He had a difficult afternoon against Arsenal but he’s been there and done it and is a quality player.
"Once he has time to adapt and settle in and we can work with him, I’m sure he will be okay and do well."
Bruce is upbeat even though his injury-hit team have suffered three successive league defeats.
He said: "We are disappointed but we mustn’t get despondent. We knew it would be difficult.
"This time a year ago we were travelling to Stockport - no disrespect intended. Now we’ve just taken on the champions of England, who are possibly as good as anyone in Europe."
Bruce has welcomed a week free from action to be able to work with newcomers Christophe Dugarry, Jamie Clapham and Stephen Clemence, and after Saturday’s clash with Blackburn there will be a fortnight’s break before their next game.
He said: "Once people get to know each other and what their strengths are, they will fit in."
Bruce is optimistic injured central defensive pairing Darren Purse and Kenny Cunningham will be back in contention for the trip to Ewood Park.
Club record signing Clinton Morrison and midfield dynamo Aliou Cisse will also be available after suspension.