Cesc Fabregas believes Barcelona's players will be put to the test by the absence of Lionel Messi from their ranks in Tuesday night's Champions League clash with Celtic at Parkhead.
The 26-year-old Argentina forward injured his thigh in the 2-0 win over Almeria on Saturday, ruling him out of the Group H clash in Glasgow.
At Barca's pre-match press conference at Celtic Park, most of the focus was on how the visitors will cope without their talismanic superstar, and Fabregas acknowledged the rest of the forward players will have to step up their efforts if the loss of Messi is not to prove significant.
The former Arsenal midfielder said: ``It is a test because we always want him in our team.
``Obviously Lionel is the best player in the world, I don't even have to say that and you obviously will miss a player of his talent and dedication.
``We rely on him a lot. He is the best player, the one that scores more goals, the one that does the offensives tasks. He is always there for us, he gives assists, he is the best.
``He can win a game at any moment so we are sad for that but you cannot feel sorry for yourselves because you are missing a great player.
``Without Messi we will have to take more responsibility.
``I think we all have to step up and make sure that we don't feel his absence, and show we can play great football without him.
``When he is not there we have to adapt the situation and players like Neymar, myself if I play, Alexis Sanchez, Cristian Tello, Pedro Rodriguez; we have to step up and do the job that a striker is made for which is scoring goals and giving assists.
``I think tomorrow is a test in that way.''
Fabregas believes 21-year-old Brazilian star Neymar could be the one Barcelona player capable of one day reaching the levels of Messi.
``He is a very talented player, very quick and has the skills to get away from you easily,'' the Spain international said.
``He is already a star but this boy will have a lot to say in the future of football.
``It is up to him. Everything is in his hands.
``He came here to learn, to compete, to fight, to grow up as a player and a person.
``He is still a boy and in the future we will be talking about him as one of the greatest.''
Home boss Neil Lennon believes the absence of Messi is a boost for Celtic, but insists it is also ``tinged with sadness''.
Lennon, whose side lost their Group H opener 2-0 to AC Milan at San Siro, said: ``It is obviously very good news for us because he is the best player in the world.
``However, it is tinged with sadness because it is always fantastic to see the great players play here in Glasgow.
``We are looking forward to the game, we welcome Barcelona with open arms and we are hoping it is going to be another great occasion.''
Lennon, whose side famously beat the Catalan giants 2-1 at Celtic Park last November on their way to the last 16 of the competition, believes Barca will be instantly recognisable even without their Argentinian superstar.
``Our approach will be the same whether Messi plays or not,'' said the Northern Irishman.
``Barcelona don't change their system, they don't change their style of play really and 4-3-3 is just what they believe in. It has worked well for them very well over the years.
``It would be fantastic if we could get something out of it like we did last year.
``We didn't really budget for it, as it were, in both the games last year, so if we can get something it will be a huge bonus for us.
``It will be very much at times containment; to limit Barcelona to as few chances as we can and at the same time maximise the opportunities that we get, as we did last year.''