Pep Guardiola's side were eager to make a statement after allowing both Real Sociedad and AC Milan to snatch draws in the last seven days and did so in style in Saturday's La Liga clash at the Nou Camp.
Lionel Messi started and finished the scoring en route to an impressive hat-trick while David Villa scored two, Cesc Fabregas and Xavi grabbed one each and defender Roversio scored an unfortunate own goal.
But it is Valencia who stop the standings after a 1-0 win at Sporting Gijon courtesy of a solitary Roberto Soldado goal.
Soldado slotted home after half an hour as Valencia extended their 100% record after three games.
Fredi Kanoute's strike early in the second half was enough for Sevilla to see off Real Sociedad and maintain their unbeaten start to the campaign.
In a game of few real chances, Kanoute capped a neat move with a powerful close-range finish eight minutes into the second half.
Ikechukwu Uche's second-half header was enough to give Granada their first La Liga win in 35 years, 1-0 over an out of sorts Villarreal.
The Nigerian striker, on loan at the Andalusian side from Villarreal, had earlier passed up the best opportunity of the first half but made amends early in the second with a fine header from Dani Benitez's cross.
Martin Demichelis' first-half header was enough to hand Malaga all three points with a 1-0 win away at Real Mallorca.
In a game of few chances Santi Cazorla was acrobatically denied by Dudu Aouate before Demichelis' header from Cazorla's cross was deflected in off Pablo Caceres.