Brendan Rodgers insists concentration will be key if Celtic are to get past Valencia in their Europa League last-32 tie.
The Hoops are 2-0 down from the first leg on Thursday night after goals from Russia international Denis Cheryshev and debutant striker Ruben Sobrino gave the visitors a comfortable win.
The Spanish side will be favourites to finish off the job at the Mestalla Stadium next Thursday night where Rodgers will be looking for the focus that was missing too often at Parkhead.
The Northern Irishman said: "The lessons are you need to really concentrate.
"It is so important. You can get away with it domestically sometimes but certainly at this level against good players, if you bring pressure on to yourselves it makes it difficult for us.
"We have to have that belief. We have got good players and we might have one or two back for then but we need to defend and concentrate well in key moments and if we get the first goal then it could set us up for a really good second leg.
"We have to try to learn from it. We have a lot of young players, we have to take that on board and take it on the chin.
"We go next week to Valencia, it will be a very difficult game for us but if we get the first goal then it can bring a different possibility for us."
