Dominic Fifield was at the Stadio Olimpico for the Guardian and his winged monkey has just tapped on the window of Guardian Towers to hand in this on-the-whistle Halloween dispatch.

Elsewhere in Group C, it’s finished Atletico Madrid 1-1 Qarabag. I wonder who’s angrier: Antonio Conte or Diego Simone. It’s on nights like this that players working under managers like that earn their money. Imagine having to go in and face Conte after a performance like that, eh?

It’s all over at the Stadio Olimpico, where an uncharacteristically sloppy Chelsea have been thrashed by Roma. Stephan El Shaarawy scored two and Diego Perotti bagged a third to put the game beyond visitors who were as bad as I’ve ever seen them play under Antonio Conte. Defensively, they were a total dog’s dinner. Their midfielders couldn’t hold on to the ball and their forwards were fairly toothless. Conte has plenty to think about ahead of the weekend’s match against Manchester United.

90 min: One wonders what Roman Abramovich will be thinking as he watches this debacle. There are already questions over Antonio Conte’s future and this performance is unlikely to lighten his Russian employer’s mood.

88 min: Chelsea win a corner, which Roma clear with ease. There’s zero sense of urgency from an English side that clearly knows that , for tonight at least, the jig is well and truly up. They’ve been dismal tonight and can consider themselves very lucky to be no more than three goals down. They’ll be one point behind Roma at close of play tonight. If it finishes 1-1 between Atletico Madrid and Qarabag in Spain, they’ll still be in the box seat to qualify for the group stages.

86 min: Roma substitution: Marco Perotti off, Lorenzo Pellegrini on. Perotti scored one for his team, but will rue the absolute sitter he missed.

84 min: A neat dummy from Michy Batshuayi in the Roma penalty area allows Pedro to shoot on goal. His effort takes a deflection and loops towards the far post. Batshuayi had made a run anticipating some scraps, but is muscled off the ball by a defender.

82 min: It’s been a dreadful night for Chelsea, who have gone from middling to bad to worse as this match has progressed. One bit of good news for them is that 10-man Qarabag are still holding Atletico Madrid in Spain. If that match finishes in a draw, Chelsea and Roma would remain favourites to advance from this group to the knockout stages.

80 min: It’s Courtois to the rescue again as he saves instinctively from a Kostas Manolas bullet-header from six yards. Indeed, the substitue is so impressed that he seeks out the goalkeeper for a handshake once the ball goes out of play. Nainggolan, who had curled the ball on to Manolas’s head rubs his hands either side of his mohawk in disbelief. That was an incredible save.

79 min: Radja Nainggolan picks up a pass a couple of yards outside the Chelsea penalty area and shoots for goal. Courtois flings himself to his right and claws the ball away for a corner.

77 min: Chelsea get forward without giving the ball away, but Pedro’s cross from the right is too close to Alisson, who grabs it with a minimum of fuss.

75 min: Roma double substitution: Gerson and Kostas Manolas on for Stephan El Shaarawy and Alessandro Florenzi. Chelsea substitution: Michy Batshuayi on for Alvaro Morata. El Shaarawy gets a standing ovation as he leaves the pitch.

74 min: Bakayoko loses the ball and Dzeko advances before dragging a shot wide.

72 min: The build-up to that Perotti miss a couple of minutes ago was like something you’d see at a kid’s football match. As the ball wasp layed forward to Dzeko, all three Chelsea players ran to him, leaving Perotti with acres and acres of space to run into. Only his ineptitude prevented him from increasing his side’s lead after Dzeko picked him out.

71 min: Chelsea substitution: Danny Drinkwater on for Cesc Fabregas, who started brightly, but got increasingly sloppy and was directly responsible for gifting Roma their third goal.

68 min: An unbelievable miss from Diego Perotti, who shoots high over the bar from 15 yards when completely unmarked. One again, Chelsea were an absolute mess at the back as the ball was played forward to Edin Dzeko on the counter. He held it up well, while being marked by three defenders, before picking out the completely unmarked Perotti. With the goal at his mercy, he blazed over. Chelsea’s back three have completely lost their shape and on his return to Roma, Antonio Rudiger is having an absolute shocker. He keeps getting caught far up the field, way out of position.

65 min: That really was shocking from Chelsea, whose manager will be furious with his players. After a series of botched clearances, they finally got the ball to Fabregas in midfield, only for him to play it straight to Radja Nainggolan. He played it forward to Perotti, who cut inside Pedro and shot past Courtois from 20 yards.

View image in fullscreen

Chelsea pay for their mistakes, with one blunder after another eventually costing them dearly. Cesc Fabregas gives the ball away outside his own penalty area, Perotti shoots from the edge of the area and the ball fizzes in the bottom left-hand corner past the grasping hand of Thibaut Courtois.

View image in fullscreen

62 min: Strootman picks out Diego Perotti on the left touchline. His cross is only half-cleared, the ball is sent back to him and again, Chelsea fail to clear his cross unconvincingly. Chelsea are playing really badly here tonight.

60 min: Chelsea get forward down the left touchline, with Marcos Alonso beating Florenzi with a wonderful bit of skill before undoing his good work with a wildly overhit cross.

57 min: Alvaro Morata scuffs a daisy cutter a couple of feet wide of the upright from the edge of the penalty area. He looks most unhappy with life at the moment. Gary Cahill didn’t look too impressed when he was forced to make way for Willian either, it must be said.

57 min: Meanwhile in Spain, Atletico Madrid have equalised against Qarabag. It’s 1-1 there.

55 min: Pedro fouls Edin Dzeko and the break in play allows Antonio Conte to make a substitution: Willian on for Gary Cahill. Cesar Azpilicueto moves into the back three, Pedro moves back to right-wing back and Willian takes up Pedro’s position in the front three.

54 min: Diego Perotti goes on a surging run through midfield before laying the ball off to El Shaarawy on the edge of the Chelsea penalty area. He picks out Edin Dzeko, who shoots high and wide of the upright with his left foot.

52 min: Eden Hazard gives away possession on the edge of the Roma penalty area and the home side gallop off on the counter. Edin Dzeko plays a loose pass and Cesc Fabregas lumps the ball forward towards Morata. He’s flagged for offside, but replays show the decision was incorrect.

View image in fullscreen

51 min: Alvaro Morata goes down injured after a tussle with Roma central defender Juan Jesus. He’ll live.

50 min: Roma have started the stronger of the two sides in the opening minutes of this second half and are barely giving Chelsea a sniff of the ball. “Considering they’re 2-0 down they’ve been very passive for the past five minutes of this second half,” says BT Sport pundit Owen Hargreaves.

47 min: Diego Perotti finds himself in acres of space on the left flank and dinks a cross into Edin Dzeko on the edge of the six yard box. He attempts to guide the ball home inside the far post with the outside of his right boot, but doesn’t get decent contact on it and steers it wide. The idea was good, but the execution left plenty to be desired. A good chance goes begging.

46 min: There are no changes on either side as Roma get the ball rolling for the second half. Elsewhere in this group, Qarabag lead Atletico Madrid 1-0 in Spain - a state of affairs few right-thinking people were expecting.

Roma are 2-0 up at the break, having opened the scoring in the first minute with an excellent strike off the outside of the boot from Stephan El Shaarawy. A dreadful mistake by Antonio Rudiger on his return to Roma allowed El Shaarawy to double his and Roma’s tally of goals for the evening and they’ll be happy with their performance at the break. Chelsea don’t look out of it, mind - they’ve been second best, but not without their chances. Eden Hazard has gone close, while Tiemoue Bakayoko has missed a sitter.