The Portuguese coach bemoaned the state of modern soccer players' supposed fitness levels after his Blancos were slenderly beaten thanks to a solitary Benat strike.
Benat scored the only goal of the game against los Blancos, though Karim Benzema had what looked like a perfectly-fine strike ruled out for offside and, according to the coach, a penalty shout denied by officials.
"After a difficult week and some conflict with his players, the fans of Betis have helped [coach Pepe Mel’s] team win,” Mourinho told reporters after the match. “I've congratulated the Betis players because they left everything on the pitch and fought with a spirit of sacrifice.
"[The referee] was hugely at fault for a wrongly-disallowed Benzema goal and a clear penalty in the closing minutes. But [Betis] deserve my respect because they outplayed Real Madrid."
The former Inter boss was clearly not in a complimentary mood towards his team, adding: "We started well, but only a little bit better than we played for the rest of the game."
But while acknowledging that fatigue may have been a factor following the 1-1 draw with Manchester City midweek, the 49-year-old bemoaned a world where fit, young players are unable to play twice in four days.
"I try to be fair and objective, and when my team lose, I do not seek excuses or blame other things,” he added. “Obviously some players played Wednesday who could not play today.
“Obviously there are other teams that have an easier match calendar but we are talking about top professionals and you have to take into account mental toughness, ambition and spirit.
"A player of 23 or 24 years should be able to play two games in four days. As always, because I speak out, and I’m the only one who has spoken out, I’ll be the bad guy."
Mourinho continued: "When we win, we all win, but when we lose, the coach loses. Why is it my fault?
"It's possible that we could finish the season 11, 13 or nine points behind Barcelona. The Liga race is still open but we're neither optimistic nor pessimistic. I can't focus on a single competition."
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