Carlos Sainz says he has no issues with Red Bull remaining in control of his Formula 1 career, conceding that he owes it to the company.
Earlier this season there was some tension between Toro Rosso driver Sainz and Red Bull bosses after he expressed his desire to move on, and a potential move to Renault appeared to be blocked.
However, the negotiations behind the change of engine for 2018 subsequently created an opportunity for him to join the French manufacturer on a one-year loan.
"In a way I understand how they deal with you, you are actually in their hands, and I've been in their hands these last couple of months, and they've dealt with it perfectly.
"It's something to be very thankful about, and I've already expressed that to Helmut Marko."
Sainz insisted that his ambition to move up the grid should be seen as a positive.
"I've never had frustration at Toro Rosso," said the Spaniard. "And I think my results this year prove it. A frustrated driver would never have done the results I've done this year.
"I was just ambitious, very ambitious I think, and Red Bull also wants to see ambition in their drivers, as they've seen with me.
"From that point onwards, after all the situation in June, I've left it up to Red Bull, and they've done exactly the best for themselves and for me.
"That's why I'm always going to be so thankful about it. They're happy, I'm happy, and I'm still a Red Bull guy."
Sainz added it was simply time to move on after three years with the Faenza outfit, which was always designed as a training ground for rookies.
"I think Toro Rosso was created to build young drivers, to make them become experienced enough to jump to the Red Bull team," he said.
"The opportunity never came for me to jump to the Red Bull team, but another opportunity came, with the same power unit, with someone they have a relationship with, and they took this decision.
"It's nice for me, it's nice for them, it's nice for Renault."