Arsenal face Barcelona in the UEFA Champions League on Wednesday evening attempting to do the improbable.

The north London side go to the Camp Nou with a 2-0 deficit to try and overturn, after a Lionel Messi brace put the Spanish giants clear at the Emirates Stadium.

The result leaves Arsenal facing yet another Champions League disappointment at the round of 16, having been defeated at the same stage this time last season by Monaco.

After such a string of poor results since the turn of the year, Arsene Wenger’s position at the club has been questioned and reports have even suggested he could be sacked.

Calum Chambers did not travel with the squad to Barcelona, while Laurent Koscielny did, meaning that the French defender is likely to be brought back into the starting XI.

But who will he be in place of – the quicker, more agile Gabriel or the disciplined, well positioned Per Mertesacker?

David Ramos/Getty Images Sport Start slideshow