When Sainz started out in the British and European F3 categories in 2012, we reported that he was doing so with the direct backing of Cepsa.

The Spanish oil company has also been Toro Rosso's major backer.

But while Red Bull remained undecided recently over promoting Sainz into F1 for 2015, it emerged that Cepsa was contemplating leaving Toro Rosso.

Spain's El Confidencial reported last month that Toro Rosso contemplating about whether to keep Jean-Eric Vergne on board next year "could be interpreted as pressure on Cepsa not to withdraw".

Ultimately, Sainz was signed up, and the newspaper now reports: "In the end, the oil company will continue to sponsor the Italian team".

Red Bull's driver programme manager Dr Helmut Marko, however, insists that 20-year-old Sainz "convinced us" by winning the Formula Renault 3.5 title.

And he described the Spaniard's Abu Dhabi test in the Red Bull car recently as "very successful".

"He's done everything we expected, so I'd say he was the natural choice," Marko added.