The French midfielder, a £4.5 million signing from Manchester City, struggled in last week's 5-0 demolition by Paris Saint-Germain in the Champions League.
It is safe to say that the 21-year-old has had better games for Celtic and he'll be aiming to get back to his best against Rangers this weekend, if he is selected.
Hoops boss Brendan Rodgers benched him for the 4-0 win against Ross County at the weekend in a decision which is unlikely to have helped matters.
But the Frenchman will be desperate to face Dundee tomorrow night in the quarter-final of the League Cup as he looks to bounce back from a difficult last week or so.
"The likes of Olivier Ntcham, who has impressed since his £4.5-million move from Manchester City, will have had his confidence bruised by an experience which saw him struggle to keep up," he told The Sunday Post.
"Don’t forget either that Moussa Dembele, who hit the hat-trick in that 5-1 win at Ibrox, has been out for a long time.
"Even if he plays, he is unlikely to pose the same threat he did then."
Celtic will be favourites to edge out their Old Firm rivals but it is not a foregone conclusion this time around.
Rodgers's side won five of the six meetings with the Gers last term, but Pedro Caixinha has improved them quite a bit, with the likes of Alfredo Morelos and Graham Dorrans coming in, and it promises to be a fascinating match.