England's Premier League teams withdrew from the European Super League on Tuesday, leaving the project in tatters just 48 hours after it was launched.
Manchester City, Manchester United, Liverpool, Arsenal, Tottenham and Chelsea signed as founding members of the 12-team league, but all have now withdrawn.
Reports on social media also suggested that Spanish club Atletico Madrid were considering leaving.
There has been huge opposition to the plans in English football and fans celebrated in the streets around Stamford Bridge as the news was reported before the team's home game with Brighton.
Should Chelsea's withdrawal be confirmed it would be a major blow to the plans for the competition set up to rival Uefa's Champions League.
The BBC reported that Blues owner Roman Abramovich is understood to have been behind the decision.
Former Chelsea goalkeeper Petr Cech, now the club's technical adviser, had come out of the stadium to persuade fans to clear the roads as the home side's team bus was held up, causing kick-off to be delayed by 15 minutes.
Cech was heard shouting "give us time" before being drowned out by angry protesters.
Liverpool footballer Jordan Henderson took to Twitter to reassure fans.
"We don't like it and don't want it to happen," Henderson said.
"This is our collective position. Our commitment to this football club and its supporters is absolute and unconditional. You'll never walk alone."
British Prime Minister Boris Johnson on Tuesday commended Chelsea and Manchester City for their reported withdrawal and called on the other clubs to pull out.
"I hope the other clubs involved in the European Super League will follow their lead," Mr Johnson said, after his government threatened a range of measures to block the English teams from taking part.
Tuesday's developments came shortly after the Super League won a preliminary ruling from a Madrid court to stop European soccer body Uefa and the sport's global governing body Fifa from imposing sanctions to stop the new formation.
The court said that Fifa, Uefa and all its associated federations must not adopt "any measure that prohibits, restricts, limits or conditions in any way" the Super League's creation.
It was not immediately clear what authority the Madrid court, which adjudicates corporate disputes, had over the Swiss-based soccer bodies and a source close to Uefa said the organisation was "relaxed" about the ruling.
The Super League has been hoping that a mix of defensive court action and momentum would lead soccer's authorities to accept their new competition within the game.
Fifa president Gianni Infantino said that the clubs could not be "half in, half out" of the established framework.
Earlier, the Premier League met with the 14 clubs not involved and said they had "unanimously and vigorously" rejected plans for a European Super League.
It said it was considering all "actions available to prevent it from progressing".
Uefa president Aleksander Ceferin told the clubs on Tuesday that it was not too late to admit they had made a mistake.
"Gentlemen, you made a huge mistake," Ceferin said. "Some will say it is greed, some complete ignorance of England's football culture.
"There's still time to change your mind. Everyone makes mistakes."
Reaction to the scheme has been scathing, with politicians and football authorities threatening to take legal action against the "dirty dozen" and possibly ban them from domestic leagues.
Juventus, Inter Milan, AC Milan, Real Madrid and Barcelona were the other five clubs who agreed to the plan.