Andre Villas-Boas's gamble in leaving Frank Lampard, fit-again Ashley Cole and even the out-of-form Fernando Torres on the bench backfired spectacularly when Chelsea lost 3-1 at Napoli on Tuesday, increasing speculation over the coach's future.
Chelsea's defeat in the first leg of the Champions League Round of 16 tie in Naples leaves them on the brink of elimination from the competition and means they have now gone five matches without a win.
With Arsenal facing a 4-0 deficit in their second leg at home to AC Milan next month, England now faces the very real prospect of failing to have a team in the quarter-finals for the first time since 1996.
Chelsea can still turn the tie around in the second leg at Stamford Bridge on March 14 and are lucky to still have the chance after a late goalline clearance by Cole, who came on as an early substitute for the injured Jose Bosingwa.
Whether Villas-Boas is still Chelsea's coach by the time Napoli come to London was the subject of some heated debate in Wednesday's English media, with reports saying he omitted the big names because of a dressing-room power struggle.
Although he is still talking confidently about his three-year project to rejuvenate Chelsea's ageing team, his billionaire boss Roman Abramovich is not noted for patiently tolerating failure.
"Speculation will continue as the results don't happen," the 34-year-old Portuguese said.
"We have to solve these mistakes at the back. We need this concentration right and this efficiency right, for sure."
A day that began badly for Chelsea with news that skipper John Terry needs surgery on a knee injury and is likely to be out for between six to eight weeks ended with them trudging off the San Paolo pitch with Villas-Boas looking stunned.
Chelsea started a roller-coaster match the better of the two sides and went ahead after 27 minutes when Juan Mata capitalised on a mistake by Paolo Cannavaro to pick his spot.
But Napoli responded with goals from Ezequiel Lavezzi and Edinson Cavani before halftime, with Lavezzi scoring a third midway through the second half to put Napoli in command of the tie as Chelsea's shocking defensive lapses continued.
"At the moment, without John, a very important player for the team, we have suffered a lot of goals recently. We had improved a lot at the beginning of January, so we have missed John," Villas-Boas added.
"But we have full belief in these players and we have to continue to work with them to get it right."
David Luiz, who has suffered a torrid time during an unhappy season, gifted Napoli their third goal with Chelsea defending like a parks team.
"It's obvious that the player has become a target," said Villas-Boas.
"He's a fantastic young player with a big future ahead of him, and he has to work to try and be a bit better. We suffered three goals. If he's linked to one, he might not be linked to the other two."
It was not only what happened on the pitch that is so alarming to Chelsea's increasingly disgruntled fans, who have been accustomed to their team winning things since Abramovich bought the club nearly nine years ago.
Reports of what is going on behind the scenes is worrying them too.
While no-one is likely to say anything publicly until they retire and write their autobiographies, the relationship between Villas-Boas and some senior players is reported to be deeply strained and may have been reflected in his team selection.
Villas-Boas, however, said his decision not to start Lampard, Cole, Torres and Michael Essien was purely tactical.
"You can have your opinion but it was based on what was the best team in my thoughts," Villas-Boas said.
"Whatever explanation I give you, in the end it would be a fantastic explanation if we'd won the game. Any explanation is now useless given the result of the game, so there's no point."
Villas-Boas continued: "I had a conversation with Ashley and Frank. Through the players that they are and the players with the experience they have, they felt they could have helped the team. That's perfectly understandable."
Only three teams have overturned a two-goal first-leg deficit since the Champions League format was introduced 20 years ago, but Villas-Boas added: "I want us to be the fourth."