Speaking to RMTV after the 2-1 victory in Budapest, Real Madrid's second pre-season friendly, Mourinho began by praising the opposition.
"First of all, thank you to FerencvĂĄros for such a good training session. They've already played their five Europa League matches, you can see they have a high intensity of play, and it was good. I liked the first half more than the second, though it doesn't surprise me," he said.
Asked to explain the drop-off, Mourinho pointed to personnel changes rather than any deeper concern.
"In the first half, it's a team we've been working with and that we've already played a couple of matches with before. There's more connection between the players who were on the pitch, very good control of the game.
"In the second half, Vini and Bernardo come on, who have no minutes and barely a couple of training sessions, and we also changed Endrick's position, so we lost a bit of the organisation of the game. But it was fine."
He went on to explain why he values mistakes as part of pre-season.
"For me, more important than doing everything well is also doing some things badly, because it allows me to think together with the players, analyse them and always improve. Let me give you a very simple example: in a league match, if you're winning 2-1 in the 47th minute, you don't play a vertical pass, you don't lose the ball and you don't end the move with a dangerous foul, like what happened today.
"In the 47th minute you have to know what you have to do, and all those small mistakes that build up in these matches are good for me."
Bernardo Silva's debut occupied much of the remaining discussion.
"Bernardo is very important, but the poor guy is another one who's had a holiday. He's the kind of lad whose head benefits from doing nothing during that period, and he's shown up in fairly poor physical shape, he has to grow. But he's a tremendous player, who gives us an outlet on the ball if he plays deeper, in the '6' or '8' position."
Asked why he pushed the Portuguese forward into a more advanced role during the match, Mourinho explained his in-game reasoning. "During the match I understood he was lacking a bit of physical strength and I moved him up to the '10' position, bringing on Cestero to give a bit more stability there. The '10' is another position where Bernardo is comfortable. He's a player who gives you three or four positions."
Mourinho also reflected on VinĂcius JĂșnior's new contract, and the caution needed with players returning from extended breaks.
"The most important thing is VinĂcius's renewal. For him, obviously, but it's a joy for all of us. He's had little training, him and Bernardo. They're players who, as happened to the others a couple of weeks ago, come into the match already tired and feel the work we've done in their legs. That's why I didn't expect Vini to pick up the ball today, run 50 metres with it and score. It's a process: he'll probably be better on Wednesday than today, and even better next Sunday in Gelsenkirchen."
Finally, he set out his thinking on squad size.
"It's a squad we want to keep short, with 20 players plus the injured ones we have for a while, like Rodrygo, MilitĂŁo or Mendy, who I don't expect to have back in the coming weeks. And in a short squad of 20, we also need a player who can do what Bernardo does, which is play in several positions."