Why Barcelona looks Unstoppable

When it became public at the end of last season that one of Barcelona's best player was leaving the Spanish club for a more lucrative offer abroad, it became a source of worry to fans of the club as to how the team would cope this season.
Major concern was who will effectively replace the outgoing player and how the new manager was going to deploy a suitable style of play that would bring in trophies this season.
With over 25 games into the 2017/2018 season, Barcelona are the only unbeaten team amongst the top 5 leagues in Europe and the only loss they suffered this season which was in a cup match was overturned in the return leg. What factors are responsible for their stellar performance this season?

-New found cohesion
The Barcelona team this season has a new cohesion unlike before and there is a new found hunger especially when the team needs a goal to fight back.

-Messi and others
Four time ballon d'or winner Lionel Messi has found his form as usual but this season he has a robust role and is unhindered in his role on the pitch. Messi can roam anywhere and seem to out-position opposing players so as to free up his team mates. This has also not stopped Messi from being a goal king.

-Barca have recruited well
With so much noise about the arrival of Ousmane Dembele, the signing with the major impact has been Paulinho. The Brazilian has been impactful with so much goals to show for it. They have also added Coutinho in January to further beef up their attack.

With upcoming games and the form of Barcelona, it is almost certain trophies will be won. Viva Barcelona, one of the best teams in Europe.