Celtic manager Neil Lennon is worried about a "spanking" by a Barcelona side intent on revenge when the two sides face each other in their Champions League Group H clash on Tuesday.
The Scottish champions sprung a huge shock at Celtic Park last November when goals from Victor Wanyama and teenage striker Tony Watt secured a famous 2-1 triumph over the four-time European champions.
Lennon knows the Catalan giants, who will be without the injured Lionel Messi, will be set on avenging that loss and has identified 'keeper Fraser Forster, who was a stand-out in Celtic's win, as being pivotal if they are to avoid a heavy defeat.
"Us getting a spanking goes through my mind, 100 per cent. That's why the goalkeeper is so important," the Celtic boss said.
"He made some big saves in the game last year, like the one he tipped over from Messi. He made some great saves in the Nou Camp as well.
"They will come aiming to rectify what went on last year so I'm very mindful of that as well.
"I don't feel any pressure going into this game, I can go out and enjoy it. But I don't want to end up getting well beaten and it affecting the confidence of not just the team but the club.
"So we have to find a way of containing them and maximising the opportunities we get."
Celtic have been handed a huge boost with the news that Argentine superstar Messi, who netted his side's consolation goal in the defeat at Celtic Park last season, has been ruled out of the clash.
Messi scored his 11th goal of the season before being substituted with a thigh injury during his side's 2-0 win over Almeria on Saturday to join Javier Mascherano on the sidelines.
His absence is a major blow for the Catalan giants, with Messi having helped himself to a hat-trick as Barca brushed Ajax aside 4-0 in the Group H opener a fortnight ago.
However, coach Gerardo Martino has players of the calibre of Brazilian sensation Neymar to call on while Celtic sold influential trio Gary Hooper, Kelvin Wilson and Wanyama in the summer.
And while Lennon feels Barca are even stronger this year he continues to believe that his side, who side put in a good performance in their 2-0 loss to AC Milan in their first match, can cause another upset.
"Probably they are better," Lennon said.
"They're unbeaten this season again. Although they beat Ajax 4-0 the scoreline flattered them. Ajax were in the game for a long period, which gives us some sort of encouragement.
"Most people will think we can't do it, that lightning won't strike twice.
"But I have to believe we can get something out of the game. We'll be in front of our own fans and that will be good for my players. Barca have international players who have played at every level all over the world.
"They have been in hostile environments so having 60,000 people shouting at them will not affect them. But I hope it will inspire our team to go out and do it again.
"We can get something. Scott Brown is playing very well just now, as is Virgil van Dijk and Efe Ambrose. Adam Matthews has had a great start to the season too.
"I was pleased with the performance in Milan. They were not fazed at all. But Barca are a different animal, home or away.
"They are the class team in this group by a considerable margin. I will try and be compact again. I have a little bit more legs in the team than I did last year.
"I have lost Wanyama and Hooper but with Van Dijk and Brown being fit this time -- and I hope James Forrest will be back -- that will give us something extra in terms of pace in wide areas."