He played every single minute of every single game at the World Cup before he went to West Ham.
He also signed from Corinithians (Brazilian).
He was one of the hottest properties around when he went to West Ham, him and Tevez, he was not some unknown player. If anything I would say he didn't live up to his promise at Liverpool. Wasn't until he got to Barca that he properly began to shine again.
Either way he was not a case of Benitez pulling a blinder by picking up this great unknown kid. He was absolutely known!