STR drivers 'must prove their quality'

That is the view of their Scuderia Toro Rosso team principal Franz Tost, who says that the time has come for his driver pairing to show they have the potential to drive for the world championship-winning team.

With Toro Rosso's third driver Daniel Ricciardo waiting on the sidelines and ready for promotion to a race seat if Buemi or Alguersuari disappoint, Tost has laid out just what is expected from his men in 2011.

"It's very simple and clear," he explained. "We are responsible in forming and educating drivers for Red Bull Racing. If we do not believe a driver can succeed at Red Bull Racing, he has no room in Scuderia Toro Rosso either.

"Though learning never ends in F1, Buemi and Alguersuari must prove now what they can do. Both of them improved very much over the winter - physically and mentally. But now we must see results."

And although Ricciardo is being considered for a race seat switch, Tost says that Buemi and Alguersuari also have a great opportunity - because one of them could be moved to Red Bull Racing for next year.

"Ricciardo has made a very good impression," explained Tost. "He has a lot of talent, and his output for the engineers is very good and useful.

"If one of our race drivers does not fulfil his expectations during this season, we will put Ricciardo into the cockpit. This puts some pressure on Buemi and Alguersuari. But, on the other hand, RBR might have to fill a vacancy at the end of 2011, so this would be a big chance."