The Atletico Madrid forward, who appeared in two friendlies for Brazil earlier this year, had been at the centre of a dispute over which country he should play for, having attained dual nationality in Spain.
He eventually chose to play for the world champions, and while Pele has admitted he is disappointed, he called on his countrymen to respect Costa's decision.
"It’s a matter of patriotism. I wanted him to represent Brazil, but maybe he wouldn’t have even been in the starting XI," he said.
"If he felt discredited in Brazil then his attitude was right. I think we have to respect his decision.
"He tried to explain that he hasn't been recognized for some time and for that reason took the decision to play for Spain. He was courageous and I understand.
"He is another player that could have represented Brazil. I have the impression that he made the right decision given that he hasn't been recognized in Brazil."
Costa - who has scored 15 goals in 13 games in all competitions for Atletico this season - could make his first Spain appearance in the friendly against South Africa on November 19.
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