Captain Graeme Shinnie believes the hammering by Celtic is a reality check of the levels Aberdeen need to reach.
The straight-talking skipper accepts losing 6-0 at Parkhead is not acceptable.
For Shinnie, Sunday’s heavy loss was particularly hard to take as it stopped a recent resurgence in form from the Dons.
Aberdeen drew 2-2 with Group G leaders PAOK in the Europa Conference League fewer than 72 hours before the Parkhead shocker.
Prior to the Euro clash in Greece, the Reds secured a Viaplay Cup final slot and also defeated Motherwell 4-2 away in the Premiership.
Losing so heavily at Parkhead brought Aberdeen crashing back to earth.
Shinnie said: “We went into the Celtic game in pretty good form, but were brought back to reality a little bit as to where our performances need to be.
“Overall, for the whole game, we were not at the races and it wasn’t acceptable.
“You single out this game – however, we won at Motherwell, get through to a cup final and had a good performance over in PAOK.
“That was three positive performances so this (Celtic) is a sore one to take.”
Exertions in Greece ‘no excuse’ for Parkhead shocker
The Dons ended the 100 percent record of PAOK in Group G.
In contrast, Premiership Hearts had been overwhelmed 4-0 at the Toumba Stadium by the Greek Super League side in the Europa Conference League play-off earlier this season.
But Shinnie was adamant the exertions in Greece were not at the root of the performance against Celtic.
He said: “It’s no excuse.
“Of course, we are not going to get away from the fact it has been a gruelling schedule.
“I think five away games in a row, there’s no getting away from that, but it’s no excuse for that performance.
“If anything, you can maybe tire towards the end, but we looked tired from the start – you can’t blame that on fatigue.
“It’s just not been good enough and, overall, like the manager said, not acceptable as a team.”
‘We need to deal with it as a team’
Aberdeen have won just one of the six games immediately following European action this season, losing three and drawing twice.
Rather than complain about the schedule, Shinnie insists the Dons must deal with it.
He would rather have the congested fixture list that comes with Euro group action and domestic cup progression than inactivity.
The 32-year-old said: “This is where we want to be.
“In European competitions and in cup finals, fighting to get into cup finals.
“We can’t use it as an excuse because it is exactly where this club wants to be.
“So we need to deal with it as a team.”
Aberdeen slow start played into Celtic’s hands
Aberdeen were 2-0 down after 16 minutes to reigning Premiership champions Celtic.
They went 3-0 behind to a second half penalty before a complete collapse late on when they conceded three goals in injury time.
The Dons have failed to win in the previous 21 games in all competitions where they have let in the opening goal.
Scotland international Shinnie said: “Going to Celtic, you know they like to start fast.
“They like to try and come at you quick and almost effectively try and win the game in the first 20 to 30 minutes.
“Being 2-0 down in 16 minutes is exactly what they wanted and it was such a slow start for us.
“That’s a frustrating part of it.”