Toro Rosso team boss Franz Tost believes that the pair could face more difficulties in their second campaign than they did as rookies if they make the mistake of believing they need to push harder.

"The second year could become more difficult if the drivers are not disciplined enough," said Tost, speaking at Toro Rosso's new Faenza factory this week.

"That means if they think [they have] to come now for their second year and show people their real potential, then they will have difficulties because they will have crashes.

"Both drivers showed already last year a very high level and they cannot drive much faster. But what they can do, because of their experience, is to get more out of the car during qualifying and also in special conditions during the race.

"That does not directly come from driving the car at the limit because they were already at the limit."

Team job

Tost believes much of the responsibility for ensuring his impressive drivers do not make mistakes this year lies with the team, which must educate both of them about what they need to do.

"It is in our hands to support the drivers, and tell the drivers to be careful in the beginning," he said.

"They must not over drive the car, especially in testing, and they need to do as many miles as possible to get familiar with the car, its technical aspects and to build up confidence."

Close battle

Although Verstappen got most of the attention last year, Tost thinks that the fight between the Dutchman and Sainz will be close throughout 2016.

"Carlos is underestimated," he said. "He did last year a very good job, but the media was focused on Max being 17 years old and coming into F1 without having a driving licence.

"But if you look to qualifying and race performance, also Carlos showed a very good performance. I am convinced this year both drivers will be close together and there will not be a big gap, otherwise I am wrong."

Verstappen praise

Although believing there will be little to choose between his drivers, Tost is in no doubts that Verstappen has the potential to become a champion.

"Max Verstappen from his talent, from his driving skills, up to now, has all the ingredients you need to win races and at the end also the championship," he explained.

"A driver in F1 always learns something. There is no driver, even not Kimi or Button [who stops learning].

"There are always new challenges in F1, with tyre or regulation changes, engines, whatever – therefore you are always confronted with new challenges.

"Max learned last year very fast, and he has learned because he has a very, very high level of natural speed.

"This natural speed is coming from his skills and also from the work his father did with him in karting, because this helped him for sure to come to this level.

"I am really, really convinced that he will have a great career in front of him, if he is at the correct time in the correct car."

Interview by Franco Nugnes