Lionel Messi has taken to social media to respond to critics who have expressed concern over his recent form for  Barcelona.

The forward, 26, has failed to score in his last four Liga appearances, something that has not occurred since April 2011, on the back of recovering from a thigh injury.

And in a post on the social networking site Weibo, Messi discussed Friday’s Catalan derby with Espanyol, which the Blaugrana won 1-0 thanks to an Alexis Sanchez goal, before touching on the issue surrounding his fitness.

“Games against Espanyol are always difficult,” AS.com reported.

“Physically, I am not 100% yet, but with games under my belt I’m sure I’ll get into my stride.”

Barcelona play host to AC Milan in their Group H Champions League fixture on Wednesday, with the Catalan outfit looking to firm up their position at the top of the group