Webber paces opening session at 'Ring.

Mark Webber kept Red Bull Racing at the head of the timesheets as the German Grand Prix opened for free practice under moody skies at the Nurburgring.

On his team-mate's home turf, the Australian set the early benchmark at 1min 33.082secs, leading the field by nearly four-tenths of a second, as the rain held off long enough for all drivers to get as much running as possible. The 90-minute session had been preceded by showers, and featured the odd sprinkling of rain, but remained dry for the duration.

Webber's closest opposition came from Brawn GP's Jenson Button, the championship leader hoping that the team's early summer endeavours pay off by getting him closer to the Silverstone pacesetters as he looks to preserve a 23-point advantage over team-mate Rubens Barrichello, with an extra couple in hand over Vettel, who carries the momentum of a crushing victory in the Briton's backyard three weeks ago.

The top five places on the timesheets featured as many different teams, with Ferrari's Felipe Massa, Toyota's Jarno Trulli and, most surprisingly of all, Force India's Giancarlo Fisichella all tightly packed, narrowly ahead of the Brazilian's team-mate Kimi Raikkonen. Germans Nico Rosberg and Vettel, and the former's Williams team-mate Kazuki Nakajima rounded out the top nine, just over a tenth shy over Massa and all within a second of Webber's ultimate pace, despite Vettel - the third German with a new helmet design this weekend - losing time to gremlins. Fernando Alonso was tenth.

While Button and Fisichella both enjoyed runs at the sharp end of the field, respective team-mates Barrichello and Adrian Sutil toiled. The Brazilian laguished at the foot of the list for some time as his BGP001 was attended to in the pits, before rebounding to a semi-respectable twelfth, while Sutil's Force India ground to a halt on the circuit, limiting the German to just six laps and 20th spot overall.

Fellow German Timo Glock was also a lot lower than expected, taking 19th position despite covering 23 laps of his local circuit. The Toyota driver was a hundredth slower than 18-th placed Heikki Kovalainen, whose McLaren colleague Lewis Hamilton was 13th.