The defender moved to La Real last summer on-loan from West Ham United.
Aguerd told Marca: "I came to Real because of the conversation I had with Imanol (Alguacil, coach). For me, as a footballer, the coach's trust is very important and Imanol's call changed everything.
"I saw that he was willing to help me, I thought that I could also help the team, and I was clear about that."
He also said, "We already beat Barcelona, which for me is the best team in the world this year, we drew against Atlético and, although we lost to Madrid, we played a great game. Of course we can go to the Champions League, if they already played there last year and played in the round of 16 against PSG.
"We have to think about that objective. If we can't, then we have to play in Europe. And we have to try to go far in Europe and the Cup. If Real has already won one recently, it means they can do it again."