Madrid - European giants Real Madrid and Manchester United exchanged recriminations on Tuesday after goalkeeper David de Gea's proposed move to the Spanish club broke down at the 11th hour.
Madrid accused United of sending the documents needed to complete the deal after the Spanish deadline had passed, but the English club laid the blame at Madrid's door and said they were "delighted" by the outcome.
Madrid seemed set to conclude the long-running transfer saga late on Monday with a deal worth between €30 million and €40 million and involving Costa Rica goalkeeper Keylor Navas joining United.
But Spanish league sources confirmed that the player had not been registered and Madrid admitted they had sent the required documentation to the league after the window closed at midnight local time on Monday.
"Manchester United introduced into the Transfer Matching System (TMS) the details for the transfer of David de Gea, not those for Keylor Navas, at 00:00 Spanish time, sending simultaneously to Real Madrid the signed transfer contracts," Madrid said in a lengthy post on their website on Tuesday.
"Real Madrid received the complete documentation at 00:02 and tried to access the TMS, but this was already closed.
"Madrid, facing the possibility of a contentious situation in the transfer of the player, decided to send the contracts to the Spanish Professional League, even knowing the deadline had already passed.
"In conclusion, Real Madrid did everything necessary in every moment to try to finalise these two transfers."
A few hours later, United responded with a statement of their own in which they said that they had acted "appropriately and efficiently".
United said Madrid had returned an incomplete version of a key document, made "major" late changes to documentation and had sent the documents needed to cancel De Gea's contract just five minutes before the deadline.
United claimed that they had uploaded the transfer agreement on to the TMS before the deadline and said that the deal fell through because Madrid did not upload documentation relating to De Gea in time.
"Manchester United acts appropriately and efficiently in its transfer dealings," United added.
"The club is delighted that its fan-favourite double Player of the Year, David de Gea, remains a Manchester United player."
Despite Madrid's long-standing interest in De Gea, negotiations between the two clubs for the player did not begin until Monday.
Madrid have not indicated whether they intend to appeal to football's governing body FIFA in an attempt to force the transfer through.
FIFA refused to comment on the specific details of the case when contacted by AFP on Tuesday, but confirmed that no appeal had been lodged by any of the parties involved.
De Gea has just one year left on his contract at Old Trafford, meaning he could join Madrid for free next year if the transfer does not go through now.
The Spanish press slammed Madrid's failure to deliver their prized target in the transfer market, with the front pages of sports newspapers Marca and Sport describing the situation as "ridiculous".
The Spain international has not featured in any of United's six games so far this season, with manager Louis van Gaal claiming the 24-year-old had lost "focus" due to Madrid's interest.
Madrid were in the market for a goalkeeper after Spain captain Iker Casillas ended his 25-year association with the club by moving to Porto in July.
De Gea joined United from Real's city rivals Atletico Madrid in 2011 and despite a shaky start went on to shine, winning the club's fans' and players' Player of the Year awards for the past two seasons.
However, he refused to sign a new deal with United due to his desire to return to Spain with Real.
A stand-off between the two clubs ensued, with United also expressing their interest in Madrid captain Sergio Ramos before he ended speculation over his future by signing a new five-year deal.