He has however been impressed by summer signing, Scott Sinclair.
The Scottish Premiership side go into the second-leg a goal behind.
The Scottish Premiership side fell to a shock defeat in the first leg.
The former Liverpool manager was confirmed as the new Celtic manager last month.
The Northern Irishman was recently appointed as the Scottish Premiership side's new boss.
Ronny Deila will leave Celtic at the end of the season.
Celtic are looking for a replacement for the departing Ronny Deila.