In his 200th Premier League game as Chelsea manager, and 100th at Stamford Bridge, Mourinho fell to just his second defeat at Stamford Bridge after Bakary Sako and Joel Ward cancelled out Radamel Falcao’s strike.
The loss also marked Mourinho and Chelsea’s second of a stuttering defence of their Premier League crown, with the Blues on just four points from their opening four games.
The Portuguese credited Palace for their victory first and foremost post-match however, noting that the Premier League is growing more and more “difficult”.
“The first thought is to Palace,” Mourinho told reporters. “They come with everything. They were lucky but they deserve the luck.
“My team, I think we deserved more. I don’t want to say we deserved to win, because it’s not true.
“The referee did a big mistake. Clear penalty with the result 0-0 and obviously with influence in the result.
“The one with (Kurt) Zouma that I watch at half-time on television. It was a clear penalty.
“(But) I prefer to go in this order, when I say Crystal Palace first. It’s a fantastic result for them and a very good performance.
“We didn’t deserve to lose, but Palace gave us a very difficult game. The result should be a draw, which would still be bad for us. We did enough not to lose. We had good opportunities, a huge penalty appeal at 0-0.
“My two centre-backs and keeper played a very good game,” he told BBC Sport. “We had a couple of players who were not in the game. When the team is not consistent and there aren’t 10 players on the pitch at a certain level it’s difficult.
“I said before the season, it’d be more difficult to win matches against non-title candidates as they all have good players and good teams – like West Ham winning at Liverpool today.”
After Manchester City – who beat the Blues 3-0 earlier in the season – dispatched Watford to make it four wins from four, Chelsea now lie eight points adrift of their closest challengers.
Mourinho, however, is not conceding the title race at such an early stage.
He added: “We have eight points less than the leader and seven and six and five from others. In another league I would say game over.
“In the Premier League I don’t say game over because last season we had seven points to the second and in one month we lost the seven points. On January 1 we were on the same points as the second.
“This is the Premier League and I think it’s getting more difficult than before.
“The reality is that we had a bad start. Four points in four matches is a very bad start.”