Lewis Hamilton has suggested the recent mudslides that badly affected the Spa Francorchamps circuit have "ruined" one of the most famous corners in F1.
The Belgian Grand Prix venue was hit by severe flooding in June that in turn caused mudlsides and led to the track surface suffering considerable damage.
At the bottom of a valley, the high-speed compression of Eau Rouge was one of the worst affected corners.
After the opening two practice sessions ahead of this weekend's race, Hamilton was left feeling the effects.
“It’s very bumpy now through Eau Rouge," said the Mercedes driver. "Something has happened and they’ve kind of ruined it a little bit.
"I don’t know if they’ve got a new patch there but there’s a massive bump right at the compression point which we have never had before.
“It’s really sharp. You feel it on the backside but I’m sure they will fix it. I think it was something to do with the mudslides and the rain or something like that.”
Hamilton unable to find Mercedes balance
Hamilton ended practice third fastest behind championship rival Max Verstappen in his Red Bull and team-mate Valtteri Bottas.
Although just 0.072secs off the pace of Verstappen's session-topping one minute 44.472s, Hamilton was left feeling there is work to do.
"At least it was dry for P2 so we got some laps in," said Hamilton, with rain forecast for the majority of the weekend.
“But the car wasn’t quite underneath me so we’ve got to do some work and try to figure that out."
Spa Francorchamps features two sectors that favour a low-downforce setup and a long middle sector geared towards high downforce, resulting in difficulties in finding the right balance.
“It’s a massively challenging circuit to try and find that balance and this morning we had it one way," he explained.
"We changed it this afternoon and it was very similar. You go faster in the first and third sectors but you go slower in the middle. Or you go quicker in the middle and slower in the other two.
“Trying to find that balance is quite tricky but it’s a great race circuit."