Manchester United are reportedly the main candidates to sign Arsenal target Joao Felix during the winter transfer window.
The Portuguese has been in-and-out of the starting line-up at Atletico this term and he is said to be eyeing a new challenge.
The Gunners are presently in a superior position to United in the league table, but the latter have a good relationship with Mendes.
They have done several deals with the super-agent in the past and are likely to have the upper hand in landing Felix this winter.
United are widely expected to propose a loan deal for the 23-year-old with a possible option to buy at the end of the campaign.
Atletico are prepared to accept a temporary package for Felix, provided they receive an £8m loan fee and his wages are paid in full.