Fabianski - deputising for the injured Manuel Almunia - had an evening to forget at Estadio do Dragao, as his costly errors saw the Gunners suffer a controversial 2-1 defeat which leaves their hopes of making it to the quarter-finals of the Champions League hanging in the balance.
Manager Arsene Wenger had spoken of his complete confidence in the "massive potential" of the young Pole in the build up to the first leg of the last 16 tie.
And Fabregas insisted the whole dressing room was behind the keeper, who looks set to be between the posts again for the visit of Sunderland on Saturday.
"He is a very good keeper," said the Arsenal captain. "He had his chance and sometimes it doesn't go your way.
"But we will stand up and support him until the end because he is a good character and I am sure he will be back."