Manchester United's "inexperience" in the transfer market led to the collapse of David De Gea's move to Real Madrid, says the Spanish club's president.
Florentino Perez drew parallels with United's failure to sign both Real's Fabio Coentrao and Athletic Bilbao's Ander Herrera on the final day of the summer transfer window in 2013.
Goalkeeper De Gea's move fell through as paperwork was not submitted in time.
"They lack experience," Perez told Spanish radio station Cadena SER.
"This same thing happened to Coentrao and Herrera."
However a United spokesman said: "The facts speak for themselves. The Football Association is prepared to back our case that documents were in on time.
"We all like to blame others but if you let one slip through your fingers into the back of the net, then ultimately the culpability is yours."
Real and United blame each other for the delay in sending the documents to finalise De Gea's transfer.
The Spanish club said they did everything they could to complete the £29m signing of the 24-year-old, but missed the deadline by two minutes.
United - who were hoping to sign Keylor Navas as part of the deal - said they submitted all of the paperwork two minutes before the 23:00 BST deadline.
Perez said the Red Devils only agreed the deal 12 hours before the transfer window in Spain closed, and then took eight hours to return documents.
He also claimed United had "showed interest" in Real's Wales forward Gareth Bale and France pair Karim Benzema and Raphael Varane during the transfer window.
In the summer of 2013 - United executive vice-chairman Ed Woodward's first transfer window after replacing David Gill - late bids for Herrera and Coentrao failed.
Midfielder Herrera, 26, eventually moved to the Premier League club in June 2014.
United have said they will change their transfer policy to prioritise world-class signings in future windows.
|Analysis from BBC Sport's Simon Stone:|
|"Even in this world of mega-money deals, some players are untouchable. As the dust settled on a hectic 48 hours at Old Trafford, a senior United source said the only thing that stopped their two-time player of the year David De Gea being in that category was the length of his contract.|
|"Though no guarantees have been offered, it is anticipated De Gea will eventually be restored to his former status as Louis van Gaal's number one keeper. It is felt if any discontent has been created by Van Gaal's refusal to pick the player so far this season, it is superficial and the relationship will soon be restored.|
|"Around Old Trafford there is also quiet satisfaction that Real Madrid have not got their man - as they did with Cristiano Ronaldo in 2009 - although the club deny completely that they deliberately held the transfer up."|