Portuguese tactician says how he spurred his players on prior to the Copa del Rey final against their rivals, and takes a swipe at his counterpart Pep Guardiola
The Madrid-based outfit had not beaten Barca in almost three years going into the game, having also lost 5-0 to the Catalan club earlier in the season.
Now the former Chelsea and Inter boss has maintained that he used his well-known motivational techniques to spur his players on to victory.
"I am a normal motivator. Before you, I have to motivate myself," Mourinho told reporters.
"When I am motivated it's easier to motivate my people. But I am exactly the same motivator and manager that lost 5-0 to Barcelona, exactly the same. I don't have a magic potion.
"I simply told my players - they're not my words, they're the words of a chap called Albert, Albert Einstein - that the only force stronger than steam, electricity or atomic energy is human will. This chap Albert was not stupid. With will you can do things."
Mourinho's Barca counterpart, Pep Guardiola, had expressed his concerns ahead of the upcoming clash between the two sides about the possibility of referee Pedro Proenca being handed the duties, before Uefa chose to appoint Germany's Wolfgang Stark as the man in charge of the encounter.
The Spaniard had been left less than impressed with a decision that saw Pedro's goal being ruled as offside during the Copa del Rey final, but replays showed that the referee's assistant had made the correct decision.
Mourinho said: "Until now we had two groups of managers.
"A very small group who don't speak about refs and a big group of managers like me who criticise refs when they make important mistakes.
"Now, with Pep's statements, we are entering a new era with a new group that only has one member - and they criticise referees who got a decision right.
"For me, it's a consequence of one thing. In his first season as manager, he lived the scandal of Stamford Bridge and, from that moment on, he's not happy when refs get it right.
"Last year, he faced Inter who played with 10 players for more than an hour. This year, he had one foot outside the Champions League and we saw what happened with Arsenal.
"In the cup final, when the ref had one decision which was absolutely correct, he criticises it."