"I always thought of what was best for Roma," lifelong Giallorossi supporter Ranieri told the ANSA news agency.
"After a game like today's, I think it is right to send a signal. So at the final whistle I went to the locker room to thank the team and decided to resign.
"Today we went on to the field with the desire to fight and win, for all those who love this club and the city.
"Every minute of my day is Roma, I have always said that losing here shakes me to the core and hurts far more than at any other club. Seeing my lads fight to the bitter end and lose, that is very painful for me.
"I thank the fans and President Sensi. Despite all the difficulties, we did a great job last season and this year.
"I am and will always remain a man of the football field, so I feel after a game like this the right thing to do is give a signal of my love for these colours and I hope my decision can help to fire up the squad.
"Sport and football have values that for me and those who put passion into this work are as important as life itself."