Roma went top of Group C after a comprehensive 3-0 dismantling of Chelsea at the Stadio Olimpico courtesy of a Stephan El Shaarawy double.
The hosts got off to a dream start when a cross into the area glanced off Edin Dzeko's shoulder and bounced right to an onrushing El Shaarawy, who blasted a right-footed shot past Thibaut Courtois for the early lead.
Chelsea saw three good chances go begging in the opening half hour, Cesc Fabregas firing wide from 18 yards, before Eden Hazard shot right at Allison in the Roma goal and Alvaro Morata skied one over the crossbar when left alone at very close range.
Roma would be two ahead at half-time after the Chelsea defence made a mess of handling a Roma ball into the penalty area and El Shaarawy ghosted in and neatly tucked a shot past Courtois for his second.
The game was effectively over just past the hour mark when a poor pass from Fabregas allowed Roma to break the other way and Diego Perotti fired his team's third goal of the night past a helpless Courtois.