Chelsea full-back Cesar Azpilicueta has hailed Filipe Luis' summer arrival to Stamford Bridge, claiming the healthy battle with the Brazilian star for the left-back role is making him a better player.
Luis joined the Blues for around £16m after garnering a big reputation in La Liga and was expected to become Mourinho's first choice left-back this season.
However, with Azpilicueta excelling in his position, Luis has seen his time restricted, making only two starting Premier League appearances in the first 13 games.
"In the big teams, there is always competition and the competition helps us to improve. I like the competition and fight for my place every day," Azpilicueta said to Marca.
The Spanish full-back kept ex-Chelsea star, and now Roma defender, Ashley Cole on the bench last season despite originally playing as a right-back.
When questioned whether he would rather to return to the right side of the pitch, in place of Branislav Ivanovic, he said: "I am actually playing even more on the left, and I feel better every day there.
"The truth is that in either of the two positions I can give my best."
Having become one of manager Jose Mourinho's key players, Azpilicueta committed his future to Stamford Bridge earlier this season, signing a new five-year contract.
When questioned whether he would consider a return to La Liga, he said: "I do not think about it.
"I am very happy here. I follow La Liga but personally I do not think about returning there. Now I'm really enjoying London. I prefer the Premier League."
Sky TV pundits Gary Neville and Jamie Carragher recently claimed the Chelsea star is the best defender in the Premier League.
When asked about their comments, the Spaniard said: "Those words flatter me.
"But also they make me eager to improve. I have always worked to be one of the best and it is clear that the more you achieve the more pressure you have.
"But I still can improve a lot. Whenever I see a game, I tried to look other players who play in my position because they teach me things to improve myself. I am lucky to train with great defenders and they are also an example for me."