Franz Tost reckons if he could combine Daniel Ricciardo's technicality with Jean-Eric Vergne's aggressiveness, Toro Rosso would have the perfect driver.
Despite scoring only a combined 26 points last season, Ricciardo and Vergne have been retained by Toro Rosso with Tost convinced the duo, aged 23 and 22 respectively, have the ability to improve.
"Both drivers showed good performances last season and both have stepped up," the STR team boss told the official F1 website.
"The important thing is that we can give them the car to perform.
"Both have shown in the past that they can win races and Championships and I am convinced that both Daniel and Jean-Eric have what it takes to develop into successful Formula One drivers."
He added: "Daniel is technically versed - he has a huge understanding of technical processes and gives superb feedback.
"Jean-Eric is more aggressive in the car and also in the race. If you could combine these qualities, yes, then you very likely would have a top driver."
However, whether one of the two has what it takes to replace Mark Webber at Red Bull Racing next season remains to be seen.
"That we don't know," Tost said. "This is pure speculation.
"Let's do the season and then let's see - first what Mark Webber is up to, secondly how our drivers develop and thirdly what kind of Red Bull youngsters will appear on our radar."
