Manchester United blocked Jose Mourinho from making his managerial return to Porto, according to the Portuguese club's president Pinto da Costa.
The Portuguese manager left Porto in 2004 having guided the club to a shock victory in the Champions League in order to take up a new challenge at Chelsea.
After spells at Inter Milan, Real Madrid and another with Chelsea, Mourinho finally replaced Louis van Gaal at United in the summer of 2016.
However, after agreeing terms with United he was approached by Porto to ask if he would comeback and manage the team on an emergency deal until the end of the season, according to Da Costa.
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