Carlos Sainz says he lost his chance to race for Red Bull at the end of 2017.
Last year, when Red Bull needed a replacement for the Renault-bound Daniel Ricciardo, Spaniard Sainz was a contender but ultimately Pierre Gasly got the call.
"It could have gone either way, me or Gasly," Sainz told AS newspaper in Melbourne.
"But I know that when I left Toro Rosso to go to Renault I really lost my ticket to go to Red Bull," he said.
"And I did it consciously and I still believe that it was a good decision for my future."
Sainz is now at McLaren, where he says his new two-year McLaren deal gives him "tranquillity".
"As you can see, I am calmer and happier than ever.
"I look at my experience with Red Bull only as positive because without them I would not have been in F1.
"Yes there were times when I would have liked more independence to make my own decisions, but deep down I must be very grateful."
However, he thinks he is in the right place at McLaren.
"Right now, if you’re not in Red Bull, Ferrari or Mercedes, I think the best place to be is still McLaren. I prefer to be here with a two-year contract and I would not change my seat for anything," said Sainz.