But the striker insists he is eager to remain with the Blues next season.
"In every training session I was visualising what it would be like in a match. I never gave up and always wanted to train more," Pato told ESPN Brasil.
"When Guus [Hiddink] gave me the chance to play I was very happy. Scoring that goal was a weight off my shoulders.
"I know that I still need more games to show my value.
"I feel that my body and mind are strong. My aim is to stay here in Europe and continue at Chelsea."
Antonio Conte - 5 things you need to know
Pato also gave his backing to incoming boss Antonio Conte, who will replace Hiddink after Euro 2016.
"Conte will do very well here," he added. "He's a guy who has a real desire to win. He revolutionised Juventus, winning a lot. I am sure that it will be the same here.
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy