Toro Rosso team boss Franz Tost says that Jean-Eric Vergne has to step up and lead the Faenza squad in 2014.

With Daniel Ricciardo departing for Red Bull as replacement for compatriot Mark Webber, Vergne becomes the senior member of the STR line-up next season, the current pair having been at the team for the same length of time.

Having led Toro Rosso's account for the early part of the season, Vergne has fallen away in the second half, having not scored a point since the Canadian Grand Prix in June. With one race remaining, the Frenchman trails Ricciardo by one place and six points - 13-19 - in the drivers' championship, despite having recorded the team's best result, ironically in Montreal.

While there hasn't been great pressure upon Vergne until now, Tost admits that Ricciardo's departure will mean a new role, particularly with rookie Daniil Kvyat coming in alongside him.

"[We will expect] that he scores many points, that we provide him with a good car and that, in his third season with us, he can show that he is there for a reason," Tost told the official F1 website, "He has to lead the team - in setting up the car and finding the best technical solutions. It should be a very interesting job for him and we will see if he can do it or not."

Tost, and Red Bull, has not been slow in dispensing with drivers that do not come up to the mark - just ask Jaime Alguersuari and Sebastien Buemi - and will no doubt be quick to compare Kvyat's progress against that of his senior team-mate.

"At Toro Rosso, we like the 'adventures' with young drivers!" he laughed, "[but] we have already worked with Daniil a couple of times.

"It started with the young drivers' test at Silverstone, where he managed good lap times, then we had an aero test in Vairano with him last week, where he did 350km, and again in Misano, [where] he did more than 400km without any mistakes, improving his lap times.

"And, on Friday in Austin, he did a good job, [albeit] unfortunately cut short by the bad weather conditions. I am really looking forward to working together with him. I have a very positive feeling. He is a driver with a quite high natural speed."

Asked whether it was fair to throw the new GP3 champion 'in at the deep end' without experience of either GP2 or the World Series by Renault, Tost insisted that, in his opinion, Kvyat proved that he deserved the opportunity to side-step those series.

"You never know when a driver shows his highest potential," he claimed, "For Red Bull, the main reason for choosing Daniil was simply the fantastic performance he has shown during this year. If you look at the GP3 races, at how powerfully he caught up and how exciting his victories were, this was really fantastic and won him the championship on his own merit.

"This is even more amazing as he came into GP3 without much preparation and, almost immediately, put his car on pole position and started to win races. As I said, he has a high natural speed - and I like to work on this basis. It will take time, of course, [but] he's got the chance now and he has to take it now.

"It is not every year that you get a seat in F1 offered to you - and when you do, you must take it. It's the same with Daniel Ricciardo with Red Bull. It is never a question of when you are ready - you'd better be ready when the chance comes!"