The Basque side already have one over the Catalan giants in La Liga, which Granero is keen to see repeated.
Speaking at a press call on Thursday, via the official club website, ex-QPR playmaker Esteban Granero believes La Real can head with confidence to the Camp Nou, with the aim of helping his manager achieve a very rare double, against the Catalan giants.
"It's a huge game and we're all preparing well. We're going into the game on the back of a win, and we want to carry on winning, so we'll be going there to try hard against one of the strongest rivals in La Liga, in their home."
Certain his team can put a dent in Barcelona's race for the title, Granero assured: "We've already shown we can compete with them and that we're strong. For example, the last match we played, we won, so we'll be hoping to win again."
Granero also admitted having kept a keen eye on the Barça-Bayern Champions League game, offering the view: "It was a beautiful and interesting game in every sense."
"You have to look at every detail and I think Bayern showed some important tips, as to how to face Barcelona, but in the end, it was a hard result for them, which up until the last ten minutes or so, had been without goals." He analysed.
Clearly aware of the threats Messi can pose, after his performance against the Bavarians, the former QPR and Real Madrid man observed: "He's an exceptional player. If he has space and favourable situations, he can make the difference. Our job will be to ensure he doesn't get those spaces, or favourable situations, the way we dealt with him at Anoeta."
Whilst the threat of relegation is something Real Sociedad have managed to avoid, since Moyes arrived at the club, consistency has been difficult to achieve, particularly away from home.
Home form has been good, with just one defeat at Anoeta, but on the road, La Real have recorded just the one victory with the Scotsman at the helm.
Despite that, Granero believes: "We're achieving what we set out to do, which is carry on improving. We're getting better all the time, creating more of our own identity, more of our own style."
"That's how we hope to carry on, not just in the game on Saturday, but in what remains of the season. This would be good, not just to finish this season well, but also to give us a boost ahead of next season."
Whether next season will see Moyes remain at Real Soceidad, is yet to be confirmed, although club president Jokin Aperribay has frequently backed his manager.