Atletico completed the signing of Costa last week after a summer of drama.
Simeone recalled to El Larguero: “We could not pay for another player of his level or higher. Last year, we were already close to recruiting him and then I spoke with (Kevin) Gameiro.
“This year, we were able to try our luck for Diego Costa. I have spoken with him several times. Costa has worked hard to make this transfer possible. If he had not made the necessary efforts to return, we would not have been able to recruit him.
“His effort is worth a lot and people want to see the Costa who initially left us.”