Grapevine: Rankings: Vettel, Hamilton fight for top

Red Bull driver Vettel has held the top spot for the last 17 weeks and heads his McLaren rival by just a handful of points.

However, the tide may turn even more in the German driver's favour as he only needs to finish to boost his current Castrol Rankings score. Hamilton has to win to maintain his score as he is defending a huge score from the corresponding race last year.

Hamilton's McLaren team-mate Jenson Button, who has risen from ninth to sixth in the past month, will improve his score by finishing in the top six. To move into the top five though, he'll have to rely on NASCAR Sprint Cup Champion Jimmie Johnson having a disastrous Brickyard 400 at Indianapolis.

Ferrari's Fernando Alonso climbed into the top 10 for the first time this week and will boost his Castrol Rankings score just by finishing in the top 15 this weekend.

However, he will only move up from his current ninth spot if Dario Franchitti (8) ends up outside the top five at the Edmonton IndyCar race.

The man with most to gain in Germany is Alonso's team-mate Felipe Massa, who did not score any Castrol Rankings points after his Hungarian GP qualifying accident last year.

With no more 2009 scores to discard, the Brazilian will only improve his position between now and the end of the season. His 62nd place will become a top 50 spot next week if he finishes in the points.

To see the full Castrol Rankings, go to www.castroldriverrankings.com