It took only six minutes for Chelsea's Club World Cup campaign to be thrown into serious jeopardy on Friday.

While leading Flamengo 1-0 in the Philadelphia early-afternoon heat, the Blues were closing in on becoming the first team to book their place in the round of 16.

Plans included an extended training camp in Miami as they honed their preparations for a sustained assault on the competition's latter stages and the £97 million first prize that would be a welcome boost to Chelsea's balance sheet.

And then, just after the hour mark, everything changed.

The lead given to them by Pedro Neto's well-taken 13th-minute strike evaporated as Bruno Henrique and then Danilo converted from close range to turn the game on its head before Nicolas Jackson got himself sent off for an idiotic challenge on Ayrton Lucas.

Wallace Yan added a late third to give Flamengo a win they thoroughly deserved both on and off the pitch, as a combative and dynamic display was mirrored by the passion and fury of thousands clad in red and black stripes, predominantly gathered behind the end that brought them such a second-half joy.

This was a performance that raises multiple questions about Chelsea and head coach Enzo Maresca. He started with Reece James in midfield and Cole Palmer stationed on the right flank. There was an irony to Palmer speaking about coveting his new No.10 shirt yesterday, only for Maresca to then ask the 23-year-old to vacate the corresponding central position where he is most effective.

It contributed to a disjointed display in which Palmer struggled to impose himself, amassing just 15 touches and three completed passes in the first half. Palmer ended up with 32 touches and the ignominy of an 82nd-minute substitution when Chelsea were down to 10 men and chasing the game.

"We tried to do something different in the game, for next season and the future," Maresca said following the defeat. "Now we have one more game, we will try to win."

But Jackson will draw more of the criticism. He was on the field for just four minutes as a second-half sub and touched the ball only once when lunging in late right in front of Salvadorian referee Iván Arcides Barton Cisneros. Jackson was sent off at Newcastle in early May in a similarly foolish act that threatened to derail their hopes of Champions League qualification. Chelsea survived without him to hit their target back then, but Liam Delap will be taking centre stage against Esperance Sportive de Tunis back at Lincoln Financial Field on Wednesday to ensure the Blues' safe passage from Group D.

It would be speculative to look too far ahead, but the probability that Chelsea won't top the group is now very real and, all things being equal, they could face Bayern Munich in the last-16. Such a game would represent a major early test of the team's credentials to win a competition the club's owners view as particularly important, not least because of the cash on offer.

On this evidence, however, Chelsea don't look up to it. Like other managers coming to the U.S. at the end of a long season, Maresca has spoken of the need to rotate and balance trying to win with managing minutes and preparing for the 2025-26 campaign. It is a difficult balancing act, but one he must do better with. This was a wake-up call, an introduction to the tournament proper with the majority of 54,019 fans against them backing a spirited team who looked hungrier and more motivated.

There is time for that to change, of course, but things just got significantly harder for Chelsea.