Leon impressed as a second-half substitute against Levante and Spanish media had speculated the summer signing from Getafe could start against Auxerre.
The 23-year-old did not even make the 20-man travelling party, though, leading to several questions during tonight's press conference - something Mourinho took a dim view of.
Clearly unimpressed at being pushed on the exclusion of Leon, Mourinho answered a third and final question on the subject before promptly leaving the press conference.
"I don't have to justify his absence. If the president (Florentino Perez) asks me, I'll tell him, but he hasn't asked me. You talk of Pedro Leon as if he was Zidane or Maradona or Di Stefano, he's a player who not long ago was playing at Getafe," said Mourinho.
"He's not called up for one game and it seems like you are talking about a great player. When he works how I want him to, he will play, and when he doesn't, it will be harder for him to play.
"I've already said Benzema will play, why not ask me what other 10 will play alongside him? That should be your first question but you ask about Pedro Leon."