Sebastian Vettel pressed the throttle and nosed his dark blue Red Bull car forward at Austin's beautiful Capitol Building

AUSTIN (Texas) - Sebastian Vettel pressed the throttle and nosed his dark blue Red Bull car forward at Austin's beautiful Capitol Building. The fans applauded and the world champion glowed.

The German won the United States Grand Prix in Texas last year, dominating from pole position. This weekend, he may not even enter the contest for a place on the grid.

The schizophrenic nature of Formula One was unwittingly laid bare on Wednesday, at an event designed to promote the race to fans whose usual sporting diet comes from American football and the baseball diamond.

They know what they are getting there but F1 rarely does what it says on the tin.

Vettel's demonstration car was powered by petrol with a V8 internal combustion. The scream of 750bhp is yesterday's technology and the four-time world champion will be driving a very different beast at the Circuit of the Americas this weekend - when he finally drives.

The new-generation hybrid cars, with their complex energy harvesting equipment and batteries allied to a tiny 1.6-litre V6 petrol engine, have been the bane of Vettel's season, so much so that he will probably need to use a sixth power pack in Austin, which is over the legal limit of five and would incur the penalty of starting from the pit lane.

That would make the stress of qualifying unnecessary and his Red Bull team may decide that they cannot risk putting needless extra mileage onto a new power pack that must last for the final three races of the season, depriving American fans of seeing the defending champion in action tomorrow.

"It remains to be seen but we have to take an extra engine at some stage and it is very likely it will be here," Vettel, who is fifth in the drivers' championship with 143 points, said before he set off on his demonstration between the grand buildings of Congress Avenue.

"We had a bad first half of the season in terms of reliability which has put us in this position.

"It is a very enjoyable circuit and qualifying is when you get everything out and try to nail that one lap and usually the time when you go quickest all weekend.

"It will be a shame to miss out on that but the points are scored on Sunday and if that is what we have to do, then we have to live with it.

"It is the regulations.

"I didn't make them but everyone has to respect them."