Chris Sutton has branded Celtic's regression in the Champions League as "unforgivable" as he slammed a "weaker" squad this term than under Ange Postecoglou.

The former Parkhead striker reckons Celtic "went backwards" in the competition as he questioned preparations for the competition.

Sutton called out late recruitment leading into the Champions League and cited the four-month period between Champions League group stage qualification and the first matchday in his criticism.

While injuries to Cameron Carter-Vickers and Liel Abada must simply be put down to poor fortune, Sutton has stated in no uncertain terms that the overall squad is of lesser quality than that which competed in the Champions League last term.

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In his Daily Record column, Sutton wrote: "Those were huge moments and, at the risk of repeating myself as I said it at the time, Celtic were not ready for them. But it’s alright me saying it. When you hear Rodgers saying it himself during the week, that’s when it really hits home because, I’m sorry, that’s unforgivable.

"Celtic knew the date of the first Champions League group matches in the second week of May when they won the title against Hearts at Tynecastle and guaranteed their place in them. That is four whole months. That Postecoglou team was building. They had their experiences of the first campaign and those that were staying could use them.

"Those who were leaving needed to be replaced properly and strengthening was also needed because, having finished the campaign with two points last term, it was clear that even the side who ended that term required more furnishing. Instead, Celtic went backwards.

"You can’t legislate for injuries to the likes of Cameron Carter-Vickers and Liel Abada, but even if those two had been available for Rotterdam, the squad on night one was still weaker than the one that finished last term’s campaign against Real in the Bernabeu. I’m going to repeat myself in one sense. That was unforgivable."