Barcelona's 4-3-3 formation is famous in the world of football. The system has barely been deviated from over the course of the last decade, although current coach Luis Enrique has always spoken of the need for tactical tweaks since taking over from Gerard Martino in the summer of 2014. The Asturian coach has altered Barca's style during his time in charge, yet he has still stuck almost always to the same 4-3-3 set-up – until now, at least. This season, his third campaign in charge, the 46-year-old is experimenting with some new formations - especially now that Lionel Messi is sidelined.

Away to Leganes recently, Luis Enrique opted for a 3-4-3 system. That is one Barca fans will know well, of course, as it was used by Johan Cruyff in the Dream Team era and also at times by Pep Guardiola. With Messi in the team, Barca won 5-1 away to the promoted side playing 3-4-3, although it reverted to a 4-3-3 or even a 4-4-2 when Leganes were attacking. Up until now, it is a system utilised sparingly by the Barca boss. More common has been the 4-4-2 tested by the Blaugrana in pre-season and also in the closing stages of the 5-0 victory at Sporting Gijon last weekend.

With Neymar dropping deeper into the role of a classic No.10, though, it was perhaps more of a 4-3-1-2 – the Brazilian moving into space behind the two forwards in a free role similar to the one occupied by Messi when he has licence to roam. Luis Enrique defends handling of Messi And it was that same system that Luis Enrique chose for the Champions League clash away to Borussia Monchengladbach on Wednesday in a 2-1 win as the Catalans came from behind to claim all three points in the second half. This time, however, Neymar struggled in Messi's role and summer signing Paco Alcacer was virtually anonymous alongside Luis Suarez. The game changed when Arda Turan came on as a subsitute and levelled the scores almost straight away, with Gerard Pique later bagging the winner.

With Messi out, Luis Enrique is having to think harder and Barca being made to dig deeper to win matches. And although the Asturian says "the idea is always the same", he is trying out these tactical tweaks to give his team an edge in the Argentine's absence. So with the five-time Ballon d'Or winner still sidelined for the trip to Celta Vigo on Sunday, there could be yet another surprise sprung by the Barca boss at Balaidos.