Fabianski was at the centre of two howlers as the Gunners slipped to a 2-1 first leg Champions League defeat at Porto on Wednesday night.
But Fabregas said: “He is strong and we have to be there for him. Sometimes when you are young in a big game, these things happen to you. You can be a little bit down but the team will be 100 per cent behind him and help him in the next game to come back to his best. It didn’t go his way but we will stand up and support him until the end because he is a good character.”
Fabianski could find himself dropped for Saturday’s visit of Sunderland, as regular No1 Manuel Almunia is rated 50/50 to return.
Midfielder Alex Song is expected to be fit, but Abou Diaby has been ruled out after injuring himself in Porto.