The Hoops were beaten 7-0 by Barcelona on Tuesday evening.
Celtic captain Scott Brown has told BBC Sport that their second half performance in the loss to Barcelona was unacceptable.
The Hoops travelled to the Nou Camp on Tuesday evening looking to get their Champions League campaign off with a surprise victory.
It proved to be a disastrous night for them though as the attacking triumvirate of Lionel Messi, Luis Suarez and Neymar ran riot to secure a 7-0 win for the La Liga giants.
In defence of Brendan Rodgers’ side, not many would have been able to stop Barca in this kind of form, but Brown insists their performance was simply not good enough.
“It’s the second half that we’re really disappointed with,” he told BBC Sport.
“To lose five goals in 45 minutes is unacceptable. Everyone is disappointed in that changing room.”
It is fair to say that this result did not take many by surprise, with Group C having looked a tough one for the Scottish champions before it even kicked off.
This result just showed the gulf in class and how monumental an effort it will be for them to try to progress to the knockout stages this year.
Indeed, even at this early stage, it is looking likely to be a straight battle between themselves and Borussia Monchengladbach for third spot and a place in the Europa League.
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