Xavi hit the post with a free-kick and Thierry Henry was denied by Van der Sar before Messi crowned a glorious personal performance with a stunning header to clinch victory with 20 minutes remaining.
It was not a quick fix as Barcelona simply continued in their imperious stride after the break, Thierry Henry tricking his way inside Rio Ferdinand only to be denied by the legs of Van der Sar.
Carlos Tevez came on at halftime for the below-par Anderson, but it did not change the course of the match with Thierry Henry skipping inside Rio Ferdinand and seeing his shot only saved by the legs of van der Sar.