Way, way too harsh.
Bloke has been asked to play out of position at LCB, where the LWB is no where near helping him defensively and there is a gaping hole in midfield. Cucurella, as our other CBs, have been fucked over and exploited.
Cucurella isn't 2014 Cesar Azpilicueta. You can't expect him to take an attacker out of the game on his own.