Barca were 5-0 up by halftime, thanks to two from Messi, one apiece from Andres Iniesta and Pedro, and an own goal from Santiago Acasiete.
World Player of the Year Messi bagged his 13th goal of the campaign after the break and substitute Bojan Krkic scored two more, completing a rout that left under-pressure Almeria coach Juanma Lillo in a delicate position.
Barcelona, who host unbeaten Real in nine days' time, climbed top on 31 points from 12 games, two clear of their arch-rivals who were hosting Athletic Bilbao in the late game.
Earlier, an equaliser from Giuseppe Rossi earned Villarreal a 1-1 home draw with Valencia to keep them third on 24 points, three clear of their local rivals.
- Related links