Helmut Marko has defended the decision to drop both 2011 Toro Rosso drivers in favour of an all new line-up, claiming that Sebastien Buemi and Jaime Alguersuari had had enough time to prove themselves.

While most people expected to see one of the Faenza outfit's drivers dropped at season end, few expected to see both Buemi and Alguersuari given their marching orders.

However, the team, which has history when it comes to dumping those it doesn't consider to be pulling their weight, did exactly that, dropping the duo in favour of Daniel Ricciardo and Jean-Eric Vergne.

Defending the decision, former F1 driver Marko, who oversees the Red Bull Driver Programme and reports directly to (Red Bull owner) Dietrich Mateschitz, says the pair weren't wining driver material.

There has been speculation that Alguersuari's fate was decided when the Spaniard rowed with Marko following an incident in Friday practice in Korea in which he held up Sebastian Vettel, a claim fiercely denied by the Austrian.

"No, not at all," he told Italy's 422race.com. Asked if there were any bad feelings with the Spaniard, he added: No, why should there be? I was the one that brought him in. And after three years you can see what sort of potential is there."

When asked why the team opted to retain Buemi as a test and reserve driver and not Alguersuari, he said: "In case something happens. He's experienced and he can do a good work on the simulator.

"A third driver is not a race driver," he continued. "He's part of the Red Bull family, he knows everything and we know him. There are not so many drivers around. We had an evaluation of the possibilities and we took what we thought was the best available for us. The simulator work is an important tool for us and he has more experience of the simulator.

"It was three years!" he added, justifying the reason for dumping the pair, "and in the case of Alguersuari two and a half."

When it was pointed out that it took a driver like (1992 world champion) Nigel Mansell many years (almost six seasons) to actually win a race, the Austrian replied: "Yes, but it's thirty years ago. You can't compare.

"Toro Rosso is a rookie team, so its function is to look for young drivers and look after their development. I think three years is enough, if you think five years, that's your opinion. But that's not the case, and we are talking a lot of money."