Victor Wanyama understands Lionel Messi is not Barcelona's only threat to Celtic in the UEFA Champions League.
The two sides meet at Camp Nou on Tuesday night for the first match of their back-to-back games in Group G.
Celtic have travelled to Spain in confident mood after taking four points from their opening fixtures against Benfica and Spartak Moscow but Barcelona pose a different challenge.
And midfield star Wanyama knows he will have to concentrate on keeping the likes of Xavi, Andres Iniesta and Cesc Fabregas quiet and not just Messi.
"It is not a case of man-marking one player. They have so many great players," said Wanyama in The Independent.
"If selected, I will have to look after whoever comes into my space and we have to try to get forward."
Manager Neil Lennon has insisted Celtic are not going to Camp Nou, one of the world's most iconic football venues, as tourists and Wanyama is also fully focused.
"We are here for football reasons and there is nothing else on our minds," he said.
"Celtic are one of the biggest clubs in the world with a history in this competition and we have a responsibility to do justice to that."