Chelsea have been left furious after their deadline-day agreement to sign Lamine Camara from AS Monaco dramatically collapsed.
The Blues had identified the Senegal international as their preferred replacement for Enzo Fernandez if his move to Manchester City went through.
But despite reaching a written agreement, the Ligue 1 outfit ultimately refused to complete the transfer.
Chelsea deal for Lamine Camara collapses at 11th hour
Chelsea had agreed a deal worth around £47 million to sign Camara from Monaco, with the midfielder also set to sign a six-year contract with an option for another 12 months.
However, the move fell apart at the very end of deadline day after Monaco refused to sign a deal sheet, according to journalist Ben Jacobs.
Fabrizio Romano also confirmed that the French club cancelled the agreement as they instead progressed with Folarin Balogun's sale to Everton.
Romano reported that Chelsea were "furious", describing the manner in which the deal was handled as "deeply unprofessional".
Camara had been one of Chelsea's leading midfield targets as they prepared for Fernandez's expected move to Manchester City, with the Blues having also explored alternatives including Manu Kone, Martin Zubimendi and Lucas Bergvall.
Chelsea miss out on Enzo Fernandez successor
The collapse is a major blow for Chelsea because they have now lost the midfielder they appeared to have lined up as Fernandez's replacement.
Camara offered exactly the sort of physicality, energy and ball-carrying ability the Blues wanted, while his age meant he could have been developed into an important part of the squad under Xabi Alonso.
Instead, the Spaniard could now be left light in midfield after Fernandez completed his record move to City.
The Blues have little to no time to find another solution, particularly with the transfer window now closed. They may have options within the existing squad, but losing Fernandez without bringing Camara has left a significant hole.
The situation is even more frustrating given that Chelsea had already done the hard work of agreeing terms.
Ultimately, they have been left empty-handed and will now have to hope their existing midfield options can cope with the loss of one of their biggest stars.