The La Liga rivals are preparing to go head to head for a place in the Champions League final.
In a typically frank pre-match press conference, Mourinho also revealed he had quoted Albert Einstein to his players and hit out at Barca counterpart Pep Guardiola regarding referee comments.
Madrid host Barca in the first leg of the semi-final at the Bernabeu on Wednesday - the third of four Clasicos in 18 days - and Mourinho will be looking to get the upper hand over his former side once again.
At the same stage of last season's competition, Mourinho helped Inter Milan knock out Barca, while last week the Portuguese guided Madrid to victory over Guardiola's men in the final of the Copa del Rey.
That 1-0 triumph at the Mestalla saw Madrid pick up their first trophy in almost three years and ended a six-game run without a win over Barca.
However, with November's 5-0 mauling at the Nou Camp - Mourinho's heaviest defeat as a coach - still fresh in the memory, the Madrid boss was keen to temper expectations.
"I don't have a magic potion to beat Barcelona," he said. "I work very hard and very seriously, and I spend many hours trying to help the people around me, but a few months ago we lost 5-0 and I was also the manager then.
"We played a good match (against Barca) at the Bernabeu in the league and we also played a good match in Valencia, but tomorrow [Wednesday] we are facing a top opponent with a top coach."
Mourinho has already impressed on his side the importance of the adage 'where there's a will there's a way', though.
He said: "I told my players there was someone called Albert, Albert Einstein, who said that there is a force more powerful than steam, electricity and atomic energy - will. And this guy Albert was not stupid. With will you can achieve things."
Madrid's cup final win, combined with Barca's injury problems in defence, led Guardiola to suggest at the weekend that his side were underdogs heading into the game.
However, Mourinho dismissed that, saying: "For me there are no favourites. It's the Champions League semi-finals - two rivals teams who know each other very well. Two teams with long traditions, two teams whose players who know what it is to be successful, who know how to win things and play big matches.
"Maybe tomorrow [Wednesday] after the match people will say that perhaps one team is slightly ahead of the other, but at the moment before playing the match, my opinion is there are no favourites."
Mourinho also feels that last week's cup final win over Barca will have no bearing on Wednesday's game, adding: "We are the same as if we hadn't won the cup. It was great to beat them but after the final we were already preparing for the league match against Valencia (at the weekend).
"Each competition is independent of the other and each match has its own story.
"It's the Champions League. We have to give our best without being influenced by what happened before."
Mourinho did admit his side will be facing a "top" team in Barca, but did not go as far as to agree with suggestions from some quarters that the Catalan side - who have won an incredible eight trophies since Guardiola took charge in 2008 - are the best team ever.
"I don't know," he said. "They're a great team, for sure. The best team ever? I don't know."
The former Porto, Chelsea and Inter boss also took a swipe at his opposite number following Guardiola's comments at the weekend that Mourinho would be happy if Portuguese referee Pedro Proenca was the official for Wednesday's first leg, as was initially rumoured to be the case.
German Wolfgang Stark was later confirmed to be the referee for the match.
When quizzed on the subject, Mourinho hit out at the Barca boss, saying Guardiola had created a new group of coaches - one that criticises officials when they make correct decisions.
"Up until now we've had two groups of coaches," he said. "[There's] a very small group who didn't talk about referees. Then there's a larger group, of which I'm included, of coaches that criticises referees when they make big mistakes."
Referring to an incident in last week's cup final, Mourinho continued: "And with Pep's statements we've come to a third group, which is a one-person group, who criticises good decisions made by the referee. I've never seen this before."