Daniil Kvyat should be a better driver when he returns to F1 and Toro Rosso in 2019.

That is the view of boss Franz Tost, who is preparing for what will be Kvyat's third separate stint with the junior Red Bull team.

"I was with Daniil in Sochi and we had a fantastic dinner together," he said.

"He's relaxed and I have the feeling he is much more measured than the year before," Tost added. "I expect a competitive Daniil Kvyat."

Kvyat, whose career hit the heights of a Red Bull seat but was ultimately left with no more than a Ferrari development role in 2019, is also "very positive" about his return.

"I'm very happy to be back," he said.

"But you cannot be happy forever. You have to recognise that there is a lot of work ahead, and I've worked hard on myself this year.

"It's very important to be in a good mental state and that is exactly what I was focusing on this year, even though very recently it was not certain that I would go back.

"Once I heard it, I was confident it would be very positive," Kvyat, 24, added.