Los Blancos lie in fourth position in the table, with league leaders Barcelona eight points ahead of them, having played the same number of games.
Mesut Ozil attracted particular criticism for his performances earlier this season, but when asked whether the Germany international's form had picked up, Mourinho was adamant that he must do more.
"What? Has he? really? He's playing same as others, they all need to improve," he told reporters at a press conference. "To win we must play well. Because when we don't, we don't win. Other teams have more luck, in certain details, and can win without playing well."
Mourinho went on to confirm that midfield duo Xabi Alonso and Sami Khedira are still missing through injury, but is confident he has enough depth in his squad to make do without them.
"I'd love to have Khedira and Xabi available to play but it's not a problem. We have other options."
Finally, the former Inter coach defended his decision not to field more youngsters in recent matches by pointing out that the club's youth academy had not produced much world class talent in recent years.
"Only two players at most from the Real Madrid youth system participated in the last three Champions League finals."
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