Sir Alex Ferguson said Barcelona were the greatest team he had ever faced after the 2011 Champions League final.

Having kept Manchester United at arm’s length, Barcelona cooly scored two second-half goals to win 3-1 at Wembley and lift their second and final Champions League under Pep Guardiola.

But what if that Barça actually got better? Well, I think they did.

That summer, the Catalan club finally signed Cesc Fàbregas, ending years of chasing the La Masia-educated midfielder, who had left for Arsenal at 16. And, though things didn’t always work out, he started finely.

Fàbregas made Barcelona a little more flexible, a little less predictable. A midfielder who was always happy to have the ball, but also happy to move away from it, creating or exploiting space.

And on 17 September 2011, a week before el Clásico, the team put on their finest ever performance.

Barcelona XI: Váldes; Mascherano, Puyol, Abidal; Xavi, Busquets, Abidal; Dani Alves, Fàbregas, Villa; Messi.

Fielding a 3-4-3 with a midfield diamond, Barça put on a show.

1-0, Messi: Busquets chips a ball out wide to Dani Alves, who heads across goal for Messi to tap in.

2-0, Fàbregas: Messi and Fàbregas switch positions as they play a one-two (false nine meets false ten?) before the midfielder volleys home.

3-0, Villa: Venturing forward from centre-back, Abidal slides a ball through to Villa, who rounds the keeper.

4-0, Rovérsio (OG):Another brilliant ball from Abidal, this one over the top, puts Villa through. His effort is saved but Rovérsio inadvertently converts a rebound.

5-0, Messi: Just one a minute later, Messi and Fàbregas combine again, the latter twisting away from defenders in the box, the former tucking home from a short pass.

6-0, Xavi: Messi brilliantly chips the ball in behind the defence, where Xavi controls the ball with one touch and lobs the keeper with another.

7-0, Villa: Fàbregas walks through the defence and leaves Villa with an empty net for his second.

8-0, Messi: Messi drifts wide, evades pressure, plays a one-two with Fàbregas (again) and is in. Goal.

As well as scoring a hat-trick, Messi hit the woodwork twice. The Argentine’s on-field relationship with Fàbregas was blossoming and it looked like the team could, somehow, actually get better.

Barcelona completed 778 passes to Osasuna’s 117. They faced just one shot on target. And, frankly, they looked like they barely got out of third gear.

They may not have gone on to win another treble that season. In fact, they missed out on both LaLiga and the Champions League.

But this performance, while they were still on top of the world, was perhaps their finest ever.