Manchester United blocked Jose Mourinho from making a return to Porto in 2016, claims Pinto da Costa, with the Red Devils refusing to sanction a short-term deal for a coach they already had lined up to succeed Louis van Gaal.
The decision to replace the Dutchman with the Portuguese was taken at Old Trafford some time before a change in the dugout was actually made official.
Mourinho committed to a contract with the Red Devils and had to wait patiently before being able to take over.
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He was offered the chance to head back to familiar surroundings for the closing weeks of the 2015-16 campaign, with Porto looking to put an emergency deal in place.