The rain prevented Caterham driver Vitaly Petrov from displaying his most fierce aggression in Saturday's qualifying session for the German Grand Prix, the Russian said.

Petrov was outqualified by teammate Heikki Kovalainen for only the second time this season, the Caterham pair in 19th and 20th, respectively, as world championship leader Fernando Alonso stormed to pole position.

“That was a bit of a difficult session after the rain at the end of third free practice changed the track conditions," Petrov said.

"We were having some issues warming up the front tires and that, combined with traffic, meant I couldn’t really push as much as I had been in the morning session," he added.

"Despite that, all weekend we’ve been progressing, doing a good job to push us in the right direction, and tomorrow I think we can do well.”

Petrov became known for a comparatively aggressive overtaking instinct and during his first two years in the sport with Lotus before dropping to the back of grid with Caterham for 2012.

He became the first Russian in F1 in 2010 and took the only podium of his career with third place at the season-opening Australian Grand Prix last year.