Toro Rosso team principal Fanz Tost has expressed his delight at retaining Carlos Sainz at his team for 2017 and is confident the Spaniard will maintain his development as an F1 driver.

The Red Bull feeder squad has confirmed it will keep Sainz as a driver for next year after it was announced by Red Bull team principal Christian Horner that Sainz would be staying inside the Red Bull fold in 2017.

The 21-year-old made his F1 debut with the team last year after winning the 2014 Formula Renault 3.5 Series championship and has continued to impress for Toro Rosso in 2016 with five points finishes in the opening eight races.

With both Red Bull seats occupied for 2017 by former team-mate Max Verstappen and Daniel Ricciardo, Sainz had been linked with a potential switch to Ferrari for next season.

Red Bull has acted swiftly to fend off any interest by taking up the option in Sainz's contract to stay within the fold and the Spaniard has been confirmed as a Toro Rosso driver for 2017.

"We are very happy that Carlos continues with us, because he has shown a very good performance since he is with Scuderia Toro Rosso," Tost said. "I am convinced that he will be very competitive and strong in 2017 as well. I am very much looking forward to next season as I am sure that Carlos will bring home very good results."

Next season Toro Rosso will switch back to using Renault power units having ditched the French manufacturer for year-old Ferrari engines in 2016.

Horner also hinted at Sainz's current team-mate Daniil Kvyat also being retained in the Red Bull fold due to the lack of options emerging in the Red Bull junior programme.