Suggestions that Jean-Eric Vergne is under pressure at Toro Rosso appear a bit premature after his team boss gave the Frenchman his backing.
Entering F1 this season after Toro Rosso opted to sack both 2011 drivers, Vergne has yet to really shine despite bagging four points to his team-mate's two.
However, when it comes to qualifying - arguably still the best basis on which to judge team-mates - the 22-year-old has come up short against Daniel Ricciardo.
The Australian has outqualified Vergne in six of seven grands prix and has also bagged the team's only two top-ten grid slots.
But despite falling short on Saturday afternoons - and suggestions that he is in desperate need of a much-improved showing in Valencia - Tost has given his French driver his backing.
"Jean-Eric Vergne, his new, a French driver. Last year he did Formula Renault 3.5 litre and of course all the tracks are new for him," he said.
"It's not so easy, Friday morning, in the first session is to learn the tracks.
"But also he is a highly-skilled driver. I rate him very high.
"He is doing a good job and improving from race to race and if we provide the drivers with a good car they show a good performance."
As for Ricciardo, Tost said: "He is a little bit more experienced, he did already 11 races last year. So far he is doing a good job.
"He is a highly skilled driver. He is committed, with a positive attitude and so far I must say he is really doing a good job."