Diego Costa: I'm ready for World Cup

Diego Costa says he is now fully-fit and ready to start in Spain's World Cup opener against Netherlands on Friday.

- 32 Teams in 32 Days: Spain
- Spain's World Cup predictions

Costa, 25, almost missed out on the tournament after suffering hamstring problems through the last month of the club season with Atletico Madrid.

However, the striker was named in Spain's final 23-man squad and came through 73 minutes of their last World Cup warmup game against El Salvador on Saturday.

Costa -- who is expected to join Chelsea this summer for 40 million euros -- told AS after La Roja training on Tuesday that the run-out against the Central American side had been very useful, while he has now put his injury problems behind him.

"I needed the game against El Salvador," Costa said. "Before I felt good and then I had the problem again. Now I am fine, fully-fit and there will be no problem for the first game."

The Brazil-born player, who now has two caps for his native and adopted countries -- all coming after making appearances in friendlies -- said he has not had any problems with either his new or former international teammates.

"Things are going well for me," Costa said. "I have been treated the way I expected. I have the support of a lot of people who understand what happened. My parents are also happy that I am here. They support my decision."

Meanwhile, Costa's new international colleague Sergio Ramos, who was named as Spain's UNICEF ambassador on Tuesday in Curitiba, says the reigning world champions are well prepared for Friday's game -- a repeat of the 2010 World Cup final, which La Roja edged in extra-time.

"First we have to get through the group stage," Ramos told Real Madrid's official website. "If anything has helped us win, it is our humility. I am really motivated to take on every challenge.

"The preparation is going great and we're all up for the game against Netherlands because it is a repeat of the last World Cup match we played in. I think we have to focus on our playing philosophy and not fear any rival, whoever it might be."

The centre-back finished the club campaign in superb form, scoring six goals in the last seven games, including the key injury-time equaliser against Atletico Madrid in the Champions League final.

And the 28-year-old said he now accepts the pressure which comes from being recognised as one of the world's best players in his position.

"It requires a lot of commitment," Ramos said. "I have won a lot of titles with the national side and with my club team but with football you can't live in the past. You have to keep on working and performing day-to-day.

"That people are saying that I'm a great defender and that they are expecting a lot from me is a lot of pressure and an added bonus for me, as it acts as another incentive to continue improving on a daily basis. That is the challenge I place on myself, to continue improving on a daily basis."