"When you lose two games against your biggest rivals is not something that makes you feel good," Modric said.
"But the important thing is that Tuesday's game is coming up so soon and there is no time to mull over what has happened. We have to focus on what we have to do and forget what happened.
"I think the Copa del Rey clash wasn't bad, as we were just missing a goal, that's why we have to continue [as we are] and trust the goal will come.
"Cristiano is a player that every team would miss. Looking for a replacement is almost impossible.
"Of course we miss him, given everything he did for the club. What the club tried to do was divide the burden among the players, and that isn't easy.
"Cristiano scored 50 goals, and you can't find someone else who can do that.
"Some had to take a step forward, and though not score 50, but at least score 15-20, or even ten goals. This is what we are missing.
"That's why I think scoring is our biggest problem this season. For example in the Copa match against Barcelona we created many chances, but a rival with their quality punishes you.
"Cristiano is not here, so we can't complain for the next ten years that we don't have him.
"The club has put faith in other players, like Gareth, [Marco] Asensio, Karim [Benzema] and has bought Mariano [Diaz] and Vinicius is doing well for his age. But sometimes things don't work out as we wont.
"The only way [forward] is to work together. Madrid will always be at the top, and then this isn't the came, we will always come back."