The result assured Brazil of a quarterfinal berth and left Mexico tied for second place in Group D with Urkaine, facing a Tuesday meeting with the Eastern Europeans for a berth in the knockout round.
Morgan Plata put Mexico ahead in the third minute with his first of two goals in the game, but Benjamin and Betinho scored before the end of the first period, and Andre (with a penalty), Buru and Jorginho also tallied by the 24th minute to stake Brazil to a 5-1 lead.
Plata converted a penalty 15 seconds following Jorginho's goal, but Mexico couldn't score again to leave itself in danger of being eliminated.
Mexico is seeking to at least match its 2007 finish, when it reached the final before losing to Brazil.
Brazil tops Mexico 5-2 at Beach World Cup