Carlos Sainz's father has expressed his "respect" for his son's decision to sign with Williams for the 2025 season, after turning down offers from both Audi and Alpine.

Williams boss James Vowles recently stated that he isn't bothered by Sainz's comments about potentially returning to Ferrari in the future, acknowledging that Williams is currently a smaller and less competitive team.

"Carlos comes with not only the ability to drive the car quickly, but also the ability to lead the team forward," Vowles told Marca. "Today, I need with and around me who are able to understand what excellence looks like. And that is not easy to find on the grid."

Both Vowles and Sainz are convinced that Williams is a team with a promising future, and Sainz has chosen to embrace this challenge instead of pursuing a seat with a works team like Audi or Alpine.

When asked about his son's decision, Carlos Sainz Sr. told Marca: "Well, I was always by his side in this."

"This year has been a difficult one for him, where even before the season started the (Lewis) Hamilton to Ferrari story came up. As a father, both myself and my nephew gave Carlos a hand, looking at all the possible options. My role hasn't changed in that."

However, earlier in the year, Sainz Sr., who has his own history with Audi at the Dakar rally, had publicly stated that his son should seriously consider joining Audi's new F1 project.

"It was his decision and we have to respect it," Sainz Sr. declared. "It was not an easy decision, nor a clear one.

"There were three or four options and in the end he is the one who had to decide his future and we support him as much as possible. And that's what we've done."

"Williams is a project that is going up. At the end of this season it has started to go better and we have to hope, and we trust in it, that next year this upward trend will continue," he added.

Sainz Sr., a two-time world rally champion, believes his son will play a key role in pushing Williams forward.

"Carlos has left a good impression at all of the teams he has been with, with his work and his know-how," Sainz Sr. said.

"The teams have improved after he arrived and that is what is important for a professional and what should always be demanded of him. I think that in this respect, Carlos is a serious driver who is very clear about where he is going," Sainz Sr. concluded.