Lewis Hamilton has played down his chances of a surprise victory in the Belgian Grand Prix, despite his impressive pace in early practice.
The reigning world champion was fastest of all on Friday at Spa, as the improvements made to his MP4-24 in recent races helped maintain an upturn in form that has happened since the German GP.
But although the car has shone, Hamilton is more cautious about what he can achieve this weekend - especially because he is losing so much time in the high-speed middle sector of the Spa track.
"The car has definitely passed the test in practice, but it is still not fantastic," said Hamilton. "It didn't feel fantastic on Friday.
"We only really had one practice session, so we still have a couple of changes to make to the car. We are still competitive, which is the most important thing. We are definitely not unhappy, but it can be better.
"We are not great on the high speed corners, and you are really starting to see it in the middle sector. A lot of the faster guys, the Red Bulls and Toyotas, they are destroying us in the middle sector. But we have KERS and a good car in the first and last sector."
Hamilton's performance in recent races have been boosted by the presence of KERS, but he believes the technology's advantage is not as great as had been hoped for.
"We only use it twice (per lap) - at the exit of Turn 1 and on the back straight," said Hamilton. "It's not a huge gain and not as big as you would have expected.
"We are quite quick in the first sector and quite quick in the last sector - but in the middle sector we are losing 0.6-0.7 seconds. We only gain three and a bit tenths from KERS, so we still have some time to find."