Chelsea crumbled as Roma moved to the top of Champions League Group C with a 3-0 victory at Stadio Olimpico last night.
Stephan El Shaarawy scored after 38 seconds and pounced on an Antonio Rudiger error to make it 2-0 after 36 minutes.
Diego Perotti struck a fine third after 63 minutes and there would be no Chelsea comeback this time as Roma moved on to eight points, one more than the Blues.
A win in Antonio Conte's first match in Italy as Blues boss would have seen Chelsea advance to the knock-out stages.
Now Conte's men need points at Azerbaijan's Qarabag before the final group clash with Atletico Madrid.
Of more immediate priority is Sunday's Premier League clash with Manchester United. N'Golo Kante was not risked here and how Chelsea missed him as Conte's tenureship comes under further scrutiny.
Chelsea surrendered a 2-0 lead to trail 3-2 two weeks ago, only for Eden Hazard to equalise at home to Roma.
Another difficult night was in prospect when Aleksandar Kolarov and Edin Dzeko, two former Manchester City players who scored Roma's goals at Stamford Bridge, combined as the hosts took a first-minute lead.
Kolarov's cross from deep hit Dzeko on the back of the head and it fell kindly for El Shaarawy to strike a crisp shot into the net. Chelsea should have been level when Alvaro Morata lifted a gilt-edged chance over after Pedro's cross.
Former Roma defender Rudiger allowed a Radja Nainggolan cross to bounce and El Shaarawy held off Cesar Azpilicueta to prod the ball in.
The decision to shift Pedro to right wing-back was exploited by Roma after Cesc Fabregas, on his 100th Champions League appearance, gave the ball away to Kolarov.
Kolarov fed Perotti, who danced by Pedro and struck a low shot under Thibaut Courtois.
A Nainggolan's shot was saved and then Kostas Manolas was denied on a night Chelsea will want to forget.