Not even a second win of the season has convinced Red Bull's team boss to nominate Sebastian Vettel 'number 1' for the remainder of the 2009 season.

Having also won in China, the 21-year-old German utterly dominated at Silverstone earlier this month but still lies 25 points behind the championship leader Jenson Button.

Complicating the issue is the strong form of Vettel's teammate Mark Webber, who despite not opening his career wins account so far this year is just 3.5 points behind in the drivers' standings.

"There's no no.1 driver," team boss Christian Horner is quoted as saying this week by the AAP news agency.

"Updates are being introduced to the cars equally at every race, and that's the way it will continue for the rest of the season," he said.

Horner admitted that the pair are equally desperate to lead the pace, but amid rumours of increasing tension denied that it is a problem.

"They're both professional drivers, they're both at different stages in their career, but they work for a strong team," the Briton insisted.

"Obviously there is a competitive rivalry, but it's a professional rivalry between the two of them."