Cristiano Ronaldo will show he is worth the world-record transfer fee of 80 million pounds ($131.3 million) that Real Madrid paid Manchester United for him, he said on Saturday.
"I respect everyone's opinion but I don't agree with these people (who have criticised the fee)," the Portugal winger told sports daily Marca in an interview.
"If Real Madrid have paid so much money it is because they wanted me and considered it good value. I am going to do all I can to play well and prove the money they paid for me has been well spent."
Club president Florentino Perez has said Ronaldo and Brazil playmaker Kaka, who Real have signed from AC Milan for around 67 million euros ($93.93 million), are the two pillars of his new project.
France striker Karim Benzema and Spain defender Raul Albiol have also been added to the squad in a spending spree worth around 215 million euros, drawing criticism from governments, rival teams and UEFA president Michel Platini.
"I think it is a fair price. If Real and Manchester United agreed this amount, there is nothing more to say," added Ronaldo.
"Great footballers cost a lot of money and if you want them you have to pay for them. I am happy to be the most expensive player in the world.
"I am used to being under pressure and am very relaxed about it. I won't think about it when I go on to the pitch so it won't affect me."
The 24-year-old said he would have fond memories of his time at United and singled out manager Alex Ferguson for special praise.
"He has been like a sporting father to me, one of the most important factors and most influential in my career," Ronaldo said.
"I have to thank him for everything he taught me ... the way of thinking, the way of making choices in my life ... he has been fundamental. He will always occupy a special place in my heart."
Ronaldo will be officially presented as a Real player at the Bernabeu stadium on Monday.