The post-qualifying fuel weights ahead of the European Grand Prix this weekend suggest that Sebastian Vettel should be worried, that Rubens Barrichello is arguably in the box seat - and that Jenson Button could just be about to get his faltering championship challenge back on-track under the Spanish sun.

Vettel may have out-qualified Button around the Valencia Street Circuit, but not only is the young German on the less favourable side of the grid in fourth, he is also carrying 7.5kg less fuel than fifth-placed Button to boot. In fact, he is carrying less fuel than anyone bar pole-sitter Lewis Hamilton, but should the defending F1 World Champion succeed in making a break at the start, on evidence of his qualifying pace he may just be able to scamper away from the chasing pack.

The list also reveals just what a good job Hamilton's McLaren-Mercedes team-mate Heikki Kovalainen did to get so close to the sister silver machine on the front row of the grid and - but for a late twitch on his fastest flying effort in Q3 - very nearly pip him to the top spot. Two kilograms heavier, the Finn is in fine form this weekend indeed.

As is Rubens Barrichello, who out-qualified team-mate Button despite having a heavier car underneath him as the experienced Brazilian seeks to stake his claim to an extended tenure at the Brackley-based outfit next year. Further down the order, title contender Mark Webber's long game in the second Red Bull RB5 - more than ten kilograms heavier than Vettel's car five spots ahead of him - could be scuppered by the fact that Valencia is a track around which it is notoriously difficult to overtake even with a light fuel load, let alone a heavy one.

The starting positions of home hero Fernando Alonso and Robert Kubica in eighth and tenth respectively for Renault and BMW-Sauber appear somewhat disappointing given the comparatively short opening stints they are both planning to run, whilst the man with the biggest smile on his face could justifiably be Nico Rosberg, who lines up a competitive seventh despite carrying the heaviest fuel load inside the top ten. The Williams star is desperate for a podium finish in 2009 - could this weekend finally deliver it?

The full list is as follows (their actual starting position is in brackets at the end):

Lewis Hamilton McLaren-Mercedes 653.0kg (1st)Sebastian Vettel Red Bull Racing-Renault 654.0kg (4th)Heikki Kovalainen McLaren-Mercedes 655.0kg (2nd)Fernando Alonso Renault 656.5kg (8th)Robert Kubica BMW-Sauber 657.5kg (10th)Jenson Button Brawn GP-Mercedes 661.5kg (5th)Kimi Raikkonen Ferrari 661.5kg (6th)Rubens Barrichello Brawn GP-Mercedes 662.5kg(3rd)Mark Webber Red Bull Racing-Renault 664.5kg (9th)Nico Rosberg Williams-Toyota 665.0kg(7th)Adrian Sutil Force India-Ferrari 672.5kg(12th)Nick Heidfeld BMW-Sauber 677.0kg (11th)Romain Grosjean Renault 677.7kg (14th)Jaime Alguersuari Scuderia Toro Rosso-Ferrari 678.5kg (19th)S?bastien Buemi Scuderia Toro Rosso-Ferrari 688.5kg (15th)Luca Badoer Ferrari 690.5kg (20th)Giancarlo Fisichella Force India-Ferrari 692.5kg (16th)Timo Glock Toyota 694.7kg (13th)Kazuki Nakajima Williams-Toyota 702.0kg (17th)Jarno Trulli Toyota 707.3kg (18th)