Antonio Rudiger's return to Roma was marred by is worst performance yet for Chelsea.
German defender Rudiger, who cost an initial £29million in the summer, was at serious fault for the second goal of the game, as he typified a woeful performance.
It was lacklustre performances all round for Chelsea, who were behind after just 39 seconds of the game.
Stephan El Shaarawy smashed home a glorious opener after Edin Dzeko's knockdown, before doubling his own personal tally later in the half.
Diego Perotti hit home an emphatic third after the break to round off the scoring.
Chelsea player ratings
Courtois 5
No chance with any of the goals. Exposed by his defence.
Luiz 4
Gave the ball away on far too many occasions here.
Rudiger 3
Horrendous mistake to allow El Sharaawy to grab his second goal.
Cahill 4
Given the runaround all night by the Roma attack.
Azpilicueta 4
Robbed in possession, gave the ball away and couldn’t prevent the second.
Fabregas 4
Floundering for the third goal as Perotti gave him the slip.
Bakayoko 4
Too much in the Roma midfield for him to cope with.
Alonso 5
Sleepy for the first goal, AWOL for the second.
Pedro 4
A good chance in the first 30 second. No impact after. Perotti went around him for the third.
Morata 5
Only he will know how he missed that first-half sitter.
Hazard 6
Did his best to lead from the front but too few followed.
Subs:
Willian (for Cahill, 55 mins) 5
Roma player ratings
Alisson 7; Florenzi 8, Fazio 7, Jesus 7, Kolarov 8; Nainggolan 8, De Rossi 7, Strootman 8; El Shaarawy 9, Dzeko 8, Perotti 8.
Man of the Match: El Sharaawy