Given their rush to cut costs, it is as well that Chelsea have not paid a deposit on rooms at the Cavalieri Hilton. Luiz Felipe Scolari’s side should still qualify from group A and could return to Rome for a second successive Champions League final in May, but it will take a dramatic improvement after this shocking setback, their heaviest defeat for 3½ years.

Scolari’s boasts about advanced bookings, which he insists were intended as a joke, came back to haunt him. In his defence, the Chelsea manager had also stated that returning to the Eternal City would entail negotiating a long and difficult road, but against opponents fourth from bottom of Serie A, this pothole was an unforeseen danger.

Scolari’s frustration will have been compounded by Chelsea storming out of the blocks before stalling after half an hour, but he can also reflect on some important lessons. To judge from their second-half performance, Didier Drogba and Nicolas Anelka’s future as a partnership is even less promising than that of Russell Brand and Jonathan Ross, while the Frenchman’s very survival at the club could be in doubt after his lacklustre attempt at leading the line on his own in the first half.

This was a reminder of his ineffectiveness at the highest level after scoring possibly the softest hat-trick in Premier League history against Sunderland on Saturday.

Anelka was not the only one to emerge from a miserable evening with a question mark next to his name — plenty of his team-mates failed to perform. Florent Malouda also seems to lack the appetite for the biggest occasions, his profligacy in front of goal an increasing problem, and John Obi Mikel’s inexperience was exposed.

For the first time this season, Chelsea looked like they are missing the guiding hand of Claude Makelele, Mikel’s predecessor in the holding role, a player so distinguished that he had a position named after him.

Scolari attributed the defeat to uncharacteristic defensive mistakes, which were plentiful. Petr Cech was beaten three times in the space of 24 minutes either side of half-time after conceding just four goals in 15 matches this season.

Roma’s first was the result of that rarest of occurrences, an error from John Terry. A quickly taken free kick after a clumsy challenge from Deco in the 34th minute found its way to Cicinho on the right byline and his cross eluded Terry and Frank Lampard for Christian Panucci to tap in unmarked against his former club.

If Chelsea’s players looked shell-shocked after dominating the opening half-hour, it was nothing compared with their emotions at the start of the second period, when Roma scored twice in ten minutes to end the match as a contest. Mikel was partially responsible for both goals. He gave Matteo Brighi the space on the edge of the penalty area to find Mirko Vucinic, whose first-time shot beat Cech from 20 yards, the first second-half goal he has conceded this season.

After going 678 minutes without being breached after an interval, Chelsea had to wait only a further ten before Vucinic scored again. The Montenegro striker dispossessed Mikel just short of the halfway line and raced upfield, being caught by the Nigeria midfield player before beating him again and shooting calmly past Cech at the near post.

While Scolari deserves sympathy for being forced to look on horrified as his players made such elementary errors, the manager was also at fault. His decision to bring on Drogba and Juliano Belletti and move to a 4-4-2 formation after a first half in which Chelsea had enjoyed 58 per cent of the possession appeared impulsive and just three minutes later it was made to look dangerously rash, as the visiting team’s attacking instincts left holes at the back. It is not the first time this season that Scolari’s desire to entertain has left his players exposed, and for all the goodwill his free-flowing side have created, the thrashings of Sunderland and Hull City will soon be forgotten if Chelsea are beaten on the biggest European nights.

The even more desperate introduction of Salomon Kalou as Chelsea chased the game was partially vindicated by Terry’s late goal, but their misery was compounded by Deco’s dismissal for two yellow cards, his second sin the trivial one of attempting to take a free kick too early. Chelsea, though, would not have been in such trouble if some of his team-mates had been sharper from the outset.