Brazil had broken the deadlock in the first half following a wonderfully worked move which was finished off by Paulinho.
However, their second goal was a much more straight-forward affair with Neymar taking a corner that was curled into the near post.
His team-mate at Paris Saint-Germain took advantage of some suspect defending among the Serbian ranks, and rose the highest to power his header past the helpless Vladimir Stojkovic in the Serbian net.
This goal put Brazil in the driving seat in the match and at the top of Group E, comfortably seeing them through to the Round of 16.