Atletico Madrid are reportedly furious with Arsenal's handling of the Thomas Partey deal and their working relationship is "irreparable".
The Gunners completed a £110million deal for the Ghanaian on deadline day, triggering the £52.5m release clause written into his contract.
Arsenal also agreed to pay the midfielder a staggering £260,000-a-week for four years and an additional £2.5m up front as a signing-on fee.
Finally, Partey's agent also received 10 per cent commission on the deal. But Arsenal failed to give Atletico adequate notice before triggering Partey's release clause, which saw them bypass having to enter into negotiations with the Spanish club.
Read more on mirror.co.uk