Pessimism was pushed aside on the night that Barcelona returned to the Champions League and took revenge on the team that dumped them out of the competition last year. It is five months since Juventus beat them 3-0 in Turin; four weeks since Gerard Piqué admitted that, for the first time, he felt inferior to Real Madrid; and two weeks since the transfer window closed, with Neymar in Paris and Philippe Coutinho still on Merseyside. The talk was of crisis and outside the stadium on Tuesday night they were collecting signatures to force a vote of no confidence in the president, Josep Maria Bartomeu.

But it was a different story inside when two goals from Leo Messi and one from Ivan Rakitic gave Barcelona the perfect start. Since that 5-1 aggregate defeat against Madrid in the Spanish Super Cup, Barcelona have played four times. Their record now reads: four wins, 12 goals scored, none conceded. The Italians were without six of the men who defeated them last season it is true, but this was still three goals and still Juventus.More importantly, this is still Barcelona. Neymar has gone but Messi is still there and he has already eight goals this season. Neymar’s replacement, Ousmane Dembélé, helped create the opening goal and offered glimpses of his contribution to come. At right-back, José Semedo is not Dani Alves, but he impressed. And under Ernesto Valverde, Andrés Iniesta, Sergio Busquets and Rakitic look like what they once were.

It would be tempting to say that the centre of gravity is the midfield again, and there may be something in that, but the real centre of gravity remains Messi. So often at the start of the moves, he was at the end of them too. His was the opening goal, just before half-time, and his second was the last. In between them, he made the second.

The first came when the ball was clipped towards Dembélé who, back to goal, controlled and turned away from his markers. The pitch opened up before him and Messi to his left. The Argentinian exchanged passes with Luis Suárez on the edge of the area and guided the ball into the far corner. One of the few men to have resisted him was defeated at last: in their forth meeting, this was the Argentinian’s first goal against Gigi Buffon.

The goal arrived at the very end of the half and underlined one of the ways Barcelona’s new front three may operate. So far Ernesto Valverde has shown little desire to simply slot Dembélé into the left-sided position vacated by Neymar. Instead, he began slightly to the right with Suárez central and Messi dropping to start moves or coming from deeper – and that was how this had arrived.

Dembélé had looked quick and occasionally excited, a shot high and wide after a mistake from Mattia De Sciglio’s mistake the half’s best opportunity. He drew appreciative applause a handful of times, beginning in the opening minutes, and was withdrawn to applause, yet he tended to run out of room. At that point Iniesta, all smooth movement and covering a lot of ground, was the man who stood out most and the ball was Barcelona’s. Juventus did not appear concerned at ceding possession, incisive when they broke, Marc-André ter Stegen making a handful of mostly routine saves. But the game soon escaped them.

Paulo Dybala’s shot at the beginning of the second half flew over the bar and then, soon after, Messi smashed one off a post. Suárez then played him in on the right a few minutes later. Racing into the area, Messi pulled across the six-yard box and although Stefano Sturaro cleared from near the line Rakitic followed up to score.

There was more. Iniesta found Messi on the right and he came inside superbly, past two men to score the third.