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.
Barca, traditionally slow starters under Pep Guardiola, had won one and drawn one from their opening two La Liga games while allowing Milan a late equaliser in the Champions League on Tuesday.
If anything it was Osasuna, unbeaten in their two previous games, who did the early pressing as Barca conceded a corner and saw Nino's diagonal cross hit the bar, though the assistant's flag was already raised.
The hosts took the lead in the fifth minute, though.
Sergio Busquets - moved back to midfield from defence - found Daniel Alves' run with a superb chipped pass and the right-back nodded the ball across for the onrushing Messi to jab it home at the far post.
Villa had an effort from the left saved by Andres Fernandez and the goalkeeper also did well to deny Messi's attempt.
If the first goal was good, the second was sublime.
Thiago, positioned on the right, flighted a well-placed pass inside to Fabregas. The Catalan chested the ball down for Messi and darted into the box to meet the Argentinian's wonderful through ball and volley home with the left foot.
Fabregas could have had a second when he broke clear but was denied by the onrushing Andres.
Eric Abidal headed against the bar with an offside flag raised anyway before Nino kept Victor Valdes on his toes once more with a decent low shot.
The woodwork featured again in the 30th minute when Messi hit the post with a header from Alves' cross.
It was seemingly over as a contest in the 34th minute when Villa made it 3-0, cutting inside to receive Abidal's pass and rounding Andres.
A long ball forward set Villa through and though Andres saved his shot, the ball deflected off defender Roversio.
It was becoming embarrassing when Barca went 5-0 up through Messi. Fabregas received Xavi's inch-perfect pass, turned nicely and laid the ball off for Messi to sweep home.
Messi hit the bar in the 50th minute with an attempted chip The sixth did come, however, and it was provided by Xavi in the 57th minute. The playmaker drifted forward stealthily to receive Messi's pass and lift the ball over the helpless Andres.
Andres did make another save soon after though when Messi brought down Alves' cross superbly before poking at goal.
The lively Nino then broke clear near the halfway line but after bearing down on goal from the left, failed to bend his shot around Valdes.
The Navarran outfit then got the ball into the net but only via a deflection of Ibrahima Balde, who was standing offside and therefore flagged.
Osasuna did not help themselves for Barca's seventh, getting into a muddle and allowing Messi to break forward and find Fabregas who squared for Villa to control and convert.
It was soon eight in the 79th minute. Messi and Fabregas played with the ball among themselves before the Argentinian showed a delightful burst of pace to slice the defence open and slot home.