The Blancos' boss praises his side's resolve to grind out the three points at the Vallecas, despite the floodlight issues which forced the fixture to be rescheduled 24 hours later
The match was originally scheduled for Sunday, but it could not be fulfilled after it emerged that vandals had sabotaged the wiring that connected the lighting system to the Vallecas, forcing Spanish authorities to move back the fixture.
However, Karim Benzema and Cristiano Ronaldo were on hand to supply Madrid with a vital win following recent defeats to Getafe and Sevilla, and the coach expressed his disdain with the waiting game they had to endure.
"It was not an easy situation for us, but it was not easy for them too," Mourinho said after the game. "You come with the mentality to play, but are then forced to wait for confirmation, and you don't play."
Mourinho then reflected on the eventual performance given by his team at Rayo, and while he admits they could have made more of a statement against their city rivals, he was enthused by the chemistry his "team" fashioned on the night.
"It was a tough game, but our team responded well," he continued. "Yes, [we could have played better], but I can point my critics to our attitude and the way my team got the job done, and today Real Madrid were a team.
"I guess if we would have played with this attitude at Getafe and Sevilla, we would have won those two games."
Meanwhile, Gonzalo Higuain insisted that all is to play for, despite the capital giants' early eight-point deficit to league leaders Barcelona.
"It was an important game," the Argentina striker acknowledged. "We came here on the back of a large gap behind Barcelona and had the intention of getting the three points. It was very difficult.
"Must we treat all of our remaining games as finals? We're at the fifth matchday, there is still much to play for. The distance is important but plenty more matches ahead. Thirty-three games is an eternity and we're going to fight until the end."
Real Madrid were made to work for their victory but their task was made a whole lot easier when Ronaldo converted from the penalty spot with 20 minutes remaining. Casado was then sent off late on for the hosts after a second bookable offence, and the manner of the performance led Higuain to draw parallels with last year's side.
He added: "At times, we seemed akin to the Real Madrid of last season, but we did not take advantage of all the chances we created. The penalty was good for us, along with the red card.
"I think the team were good overall. We still have room for improvement but we started well in the Champions League, that's a fact."