Diego Lopez believes it is "hard to define" how important Cristiano Ronaldo is to Real Madrid after he signed a new contract at the club.
The Portuguese sensation signed a three-year extension to his deal at Santiago Bernabeu earlier this month to make him the highest-paid player in world football, and Lopez feels the news of his renewal was warmly welcomed by team-mates and supporters alike.
"It's difficult to define a player of Cristiano's stature," Lopez told Bwin's official website.
"He's the best and we are hugely fortunate to have him at the club, now and for many years to come. [His renewal] is the best news for all madrisistas and for all of us [in the squad]."
Real Madrid face Atletico in a hugely-important derby clash on Saturday.
It is first encounter since Diego Simeone's men beat their neighbours to lift the Copa del Rey in May, and Lopez admits he is relishing the prospect of another battle with their cross-city rivals.
"It's a game with a huge rivalry attached and we're looking forward to it. They're matches where you see plenty of spirit and passion. It's a game where you fight to give your best and come away with three points," he continued.
"Real Madrid always have to win, and we cannot allow ourselves to slip up in any game, especially in our own stadium. Every game is unique for me but I always try to approach them in the same way.
"We're up against a very dangerous team. They have a very strong group, they're united and they know how to play well. We have to exploit their little deficiencies and impose our own quality on them.
"I hope we win, but above all, I hope it's a good game."
Finally, the Spanish goalkeeper revealed his admiration for coach Carlo Ancelotti and believes the team is beginning to adapt to the Italian's methods.
"The main thing I've noticed has been the professionalism of the group [since Ancelotti's arrival]," added the 31-year-old. "He has enormous talent, and what we're learning from him, his way of organising the group ... little by little the team is adapting to what he wants."