Lewis Hamilton says Silverstone's windy conditions weighed on his opening day of practice for the British Grand Prix.
The Mercedes driver was shadowed only by Red Bull's Max Verstappen in FP1 but could only achieve the fifth fastest lap in the afternoon session, insisting it had been a day of "hard driving" onboard his W11 Black Arrow.
"[It was] quite a difficult day, to be honest," Hamilton said. "It's always windy here, which is actually a good thing about this track, you've got some wind in different directions. But it's made it really tricky today with the car.
"The balance is not good as I'd like, so we're just going to work on it tonight and try and see if we can figure it out.
"It's not a disaster, but definitely been a hard day of driving."
In the morning, Hamilton had complained about his soft tyres graining, and in the afternoon he aborted a fast run on the soft rubber.
"We went back out and I think the tyres weren't as good as the first one," he explained.
"We'll work through it. We've got great engineers. That's the great thing about this team, we continue to dive deep into the details and hopefully make some good changes overnight.
"I think that's great to see close competitors. Hopefully tomorrow it's close with us also."
Mercedes trackside engineer Andrew Shovlin believes that Friday's exceptionally hot conditions may have impacted the W11's pace. But cooler temperatures moving forward could bring the car's performance back in line with expectations.
"Valtteri [Bottas] seemed happier with his car than Lewis but both feel that the tyres are running hot and that's making the car a bit of a handful at times on low and high fuel," Shovlin explained.
"It's quite a balancing act in terms of how you respond because we're expecting cooler weather tomorrow and need to be careful not to over-react.
"This car is competitive when we land it in the right window, and we've got a bit of time this evening and another session in the morning to work out how to do that.
"Hopefully we can finish tomorrow a bit higher up the timesheets."
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