Celtic’s chances of being in Europe in the latter half of the season evaporated when they only managed a 1-1 draw against Shakhtar Donetsk at Parkhead on Tuesday night.
They again squandered several opportunities on a Champions League night and failed to keep Shakhtar Donetsk, who also missed guilt-edged chances at the other end, at bay.
The Scottish giants have shown attacking ingenuity in the Champions League this season but Mjallby insisted that it is important to keep clean sheets as well at Champions League level.
The former defender is happy to see Celtic continue their attacking brand of football when they are in Europe again but feels they need to find a balance in their defence to progress as a team in the Champions League.
Mjallby said on BT Sport: “You need to be able to keep clean sheets in the Champions League.
“That’s what I want to see – keep this attacking brand of football but get the balance right.
“Don’t concede goals.”
Despite all the chances created, Celtic only managed just three goals while conceding ten at the other end in five games in the Champions League thus far this season.
