MADRID - Real Madrid goalkeeper and captain Iker Casillas says he's fighting to prove to coach Jose Mourinho that he deserves his place back in the side after Mourinho controversially dropped him for last month's La Liga match at Malaga.

Mourinho's surprise decision to pick inexperienced reserve keeper Antonio Adan ahead of Casillas prompted speculation about possible rifts in the Real dressing room. Meanwhile, the team lost the match 3-2 to all but end its chances of defending its title.

With just under half the season played and ahead of its game at home to Real Sociedad on Sunday, Real is seven points behind second-place Atletico Madrid and 16 adrift of archrival Barcelona.

"I have to battle, fight and try to get my place back," Casillas told a news conference as the Real players met for their first training session of 2013. "That's the goal I have and I am hopeful the coach will choose me in the starting lineup on Sunday," added the Spain international.

"What is really important is that the 11 players the coach picks do their best. The institution and the club come before Casillas."

Mourinho's side has already dropped more points this season than during the whole of its successful 2011-12 campaign, losing four games and drawing three, while Barca has yet to lose in 17 matches.

The only match it failed to win was a 2-2 draw at home to Real in October, and it will be seeking an 11th consecutive victory when it hosts city rivals Espanyol on Sunday.

Casillas acknowledged that Real's erratic form meant other teams in La Liga did not see it as such a daunting opponent this term and that it was up to the players to win back that respect.

He denied that there was any tension among the players and coaching staff.

"We can't throw in the towel. We have to keep going, run more, train more and hope the results come on the pitch," he said.

"Now, in 2013, we have to try to close the gap in the league while keeping in mind that the situation is difficult but not impossible."