"There are lots of poets in football but poets don't win many trophies."
The match will be played in Stockholm on Wednesday.
The Portuguese is a prolific winner in cup finals and has won the Champions League twice.
Ajax's team had an average age of 20 in its last match.
United's final, and now biggest, test comes in the Europa League final against Ajax on Wednesday.
Mourinho wants to rest his senior players in preparation for the Europa League final.
Mourinho says United is only focused on Stockholm.