Iker Casillas says Diego Lopez has earned the right to play in Primera Division games with performances which have taken Real Madrid to the top of the table.
Blancos coach Carlo Ancelotti has been rotating his goalkeepers all season, with Lopez playing league matches and Casillas coming in for Champions League and Copa del Rey games.
The controversial policy -- first instigated last season by Ancelotti's predecessor, Jose Mourinho -- has been criticised increasingly in the Spanish media of late.
Lopez was blamed for not stopping Gabi Fernandez's long-range strike in last weekend’s 2-2 derbi draw against Atletico Madrid, while Casillas had excelled in the 6-1 Champions League win at Schalke the previous midweek.
But the club captain told Madrid’s website that Ancelotti’s decision was understandable given how the team was playing in their domestic league outings.
"If the boss has decided that I'm to play in the Copa and the Champions League then I want to do the best I can to help the team and play well," Casillas said.
"It's been going on for a few months, and we aren't always going to be in this situation. Up until now the gaffer has gone with Diego in the league and he is playing very well.
"We deserve to be league leaders and a lot of that is down to Diego."
Madrid’s good form has led to hopes of a Liga, Copa and Champions League treble this season but, ahead of a big run of games which includes a league clasico against Barcelona at the Camp Nou on March 23, Casillas said Madridistas should not get too far ahead of themselves.
"We have to go game by game," he continued. "We mustn't speculate about who will get to the Champions League final in Lisbon.
"Now we must think about what we have to do in the month of March in order to get to the business end of the season in the best state possible and have it in our own hands."
The 32-year-old added that the point gained at Atletico was a positive as Madrid had consolidated top spot in the Primera Division, having been five points back just two months ago.
"I don't think it created any doubts," Casillas added. "[Atletico are] a hard side to beat and we knew that they were going to give their all; it is an important game and we have come out of it.
"We have to give value to the lead we have. A few months ago we were behind. We have come back into contention and are where we want to be. We have to defend our place every week."
Real Madrid currently lead Barcelona by a single point in the league with 64 points after 26 games, with city rivals Atletico three points behind.