Real Madrid star Cristiano Ronaldo admits he could be in the best form of his career but, worryingly for opposition defenses, he is still aiming to get even better.

Ronaldo will head into Saturday's Primera Division game at Almeria with his confidence sky-high after his brilliant hat-trick in midweek helped Portugal beat Sweden 3-2 and seal a place in next year's World Cup finals.

That was Ronaldo's fifth hat-trick for club and country this season alone and took his tally for 2013 to 66 goals in all competitions.

It has been a phenomenal year for the £80million man, and has led to him being installed as favourite to usurp Lionel Messi as winner of the FIFA Ballon d'Or, but Ronaldo is still looking to find ways to improve.

"In my head I always think that I can improve. My ambition is to always be better," the 28-year-old said on Spanish radio station Cadena Cope.

"Maybe you get to a level which is difficult to surpass, but I always think I can improve everything.

"Perhaps, at this point, I'm better prepared and it could be that this is one of the best moments of his career.

"I have to show a very high level and very good and I hope to maintain it until the end of my career."

There had been widespread speculation last season that Ronaldo could possibly leave Madrid in the summer, but in September he penned a new contract tying him to the Spanish giants until 2018.

That means the Portugal captain will be 33 when that deal runs out, and could conceivably mean he will end his career at the Bernabeu.

Asked about that prospect, Ronaldo said: "Yes, it's possible. I don't think too much about the future, I like to think more about the present.

"When the present is good, when you're happy and you're motivated to do things well, then you're less concerned about the future.

"But the truth is that I feel, at this moment, that I would like to finish my career here because I feel very happy, I love living in Madrid, I love playing at the best club in the world and I can't ask for any more."

Madrid return to league action after the international break looking to keep the pressure up on top two Barcelona and Atletico Madrid, who are six points and three points above Carlo Ancelotti's men respectively.

Ancelotti will have to do without Sami Khedira for the trip to Almeria with the midfielder suffering a potentially season-ending knee injury while playing for Germany. Full-back Fabio Coentrao is also struggling with a knock.