Red Bull undecided over drivers

"We have time on our side," said Marko. "We need more time to weigh up all the options and there is no hurry for us to make a decision."

The two drivers could go head-to-head again in another test once the Christmas break has come to an end. Klien already has a year's F1 experience behind him with Jaguar Racing while Liuzzi (a contracted Red Bull junior driver) won the F3000 championship and impressed with his speed in the recent Jerez test.

Red Bull is reported to have considered sharing the second seat between the two drivers, but the team's managing director David Pitchforth said recently however that this would be impractical. Klien would be uneligible to take the role of Friday test driver having competed in more than six grands prix this year.

"Klien can't do the Fridays for us, and it's not something we would like to do with a racing driver," said Pitchforth. "You've got to be committed to them and for Christian to give up the [race] seat and not do the Friday role is not something that is ideal."

Marko hinted to Austrian website F1 Welt however that this scenario is not yet out of the question: "Mr Pitchforth must remember that he is an employee and not a team owner. All decisions will be made in Salzburg."