Valtteri finished the morning session on a cold and green track in P9 with Lewis in P15. In the afternoon, Valtteri was fast enough for P3, followed by Lewis in P4.

The team focused on finding the best set-up for the recently resurfaced Istanbul track.

Valtteri Bottas: When I first went out on track this morning it felt more like rallying, it was quite far away from the normal driving standards that we're used to in Formula One. But I had fun playing around on track, experimenting with the car, it was actually quite enjoyable. The tarmac is new and very smooth, making it particularly difficult to heat up the tyre. It's crucial in these conditions to build up the temperatures to give you the upper hand. We've experienced this in winter testing before, but never quite to this extreme. We've also seen a lot of track ramp today, bringing the lap times down, which will continue over the weekend. The Soft tyre felt best overall, providing the best grip, even though we had a bit of graining on the front. Lots to learn from today, tricky to make the right decisions, not just in terms of set-up but also for the strategy of the race. We have some work to do in terms of the competitive picture too.

Lewis Hamilton: It was very difficult day today. This track is such a fantastic circuit, but the new surface made it very tricky. None of the tyres were really working for us and it felt like driving on an ice rink out there. So, you don't really get the enjoyment of the lap that you would normally get around here in Istanbul. When you're way below the temperature window, the tyres just don't work. You can go from one lap to another and find a second just because the tyres work a little bit better in one of the corners. We've got a lot of work to do to try and figure out what we can change overnight to put us in a better position for tomorrow. There are some fundamental things that you can't change on the car, but we'll just have to do the best we can. I think it will be a real fight for us this weekend, but that makes it very exciting!

Andrew Shovlin: We've not had an easy day here, the track is clearly very low grip with the new surface and others are coping better with that than we are. We appear similarly offset on both low fuel and the long runs. It seems that we find it harder than some to generate tyre temperature and whilst we'd tried a few things during the sessions to improve this, the performance gap to Red Bull still remains and Ferrari also looked like they were often ahead of us. It's clearly very unusual conditions and there's a lot of interesting learning that we can take from the data today. But we also have qualifying tomorrow and a race on Sunday and at the moment, we're not in great shape and are in for a tough time if we don't make significant progress overnight.

Check out our Friday gallery from Istanbul, here.