Sebastian Vettel says he is wary of the KERS-equipped cars at tomorrow's Hungarian Grand Prix after qualifying on the front row on Saturday.
The Red Bull driver will start from second position behind Fernando Alonso, but will have the McLarens of Lewis Hamilton and Heikki Kovalainen in fourth and sixth.
Both cars are equipped with KERS, which has proved to be a big advantage at the starts, and it is likely to be even more tomorrow on a track where overtaking is virtually impossible.
"It was a pretty difficult start to the weekend but yesterday we were struggling with the set-up," said Vettel. "Overnight we did a good step, so it should be good tomorrow but for sure the biggest challenge is the threat from cars behind with KERS.
"The KERS cars are somewhere there, it is a question of where they will pass, left or right, down into Turn One. We will see tomorrow."
The Red Bull driver, however, said he was not too worried about starting from the dirty side of the track.
"We have seen the last couple of races that it was a not a disadvantage," he added. "Rubens was able to nearly pass Mark but for sure, the advantage is the clear side but I don't think it is massive around here."