Brendon Hartley: "We had a bit of a slow start this morning because of an engine problem from the word go in FP1, so we lost a bit of time, but the team did a great job to get the car ready for this afternoon's FP2. I feel I'm getting better on the short-runs and to end up P13 isn't bad. I learned some good lessons on the longer runs and, even if we had an engine failure, the rest of the day was very positive and I got a lot out of it. I'm a lot more well-prepared than a week ago! We will now work hard tonight and I look forward to tomorrow!"

Pierre Gasly: "Not much running for me today unfortunately - I sat out in FP1 as Sean was in the car this morning and this afternoon I was only able to complete one lap... We then had an engine issue and had to stop the car. On Sunday I will have a penalty for the race... So not a good day for us, but it is what it is, we can't do much about it now. We will have a really busy day tomorrow because I don't know the track, so we'll have only FP3 to learn it and to get ready for quali and the race. We'll do as much as we can and keep pushing the rest of the weekend!"

Sean Gelael: "Finally, a completely dry FP1 session! I'm very happy with this morning's consistent weather conditions, it was a really positive session for me. I was happy with my first outing and set quite a good lap. Then, on my second set of tyres, we had a few small issues and I also got caught in some traffic, so I didn't really get any decent laps, which was a shame... But, having said that, as a team we got everything we wanted and needed from the session, so we can be pleased. Overall, I'm happy with everything I did today - a good way to end the season with the team, as this was my last FP1 of the year and to finish on a positive note is always good!"

Jonathan Eddolls (Chief Race Engineer): "A very difficult day for us all round... Unfortunately, we had a Power Unit issue on each side of the garage today. In FP1, we had an issue with Brendon's car, which meant he had really bad drivability, so he was really struggling with the car and, in the end, it was a terminal issue, so we had to stop him and fit a spare engine that was already in the pool - so he can do this without a penalty - and that meant it was the end of his session. Sean was in the other car for FP1, because we knew that unfortunately Pierre needs to take a grid penalty this event, so that's why we decided to sit him out during this morning's session. That wasn't a completely smooth session either for Sean; he also suffered drivability issues with the PU side. We thought we would get away with it going into FP2 but it also became a terminal issue in this afternoon's FP2 with Pierre... We're happy to have him back after his last race weekend in Japan and look forward to working together again. Unfortunately, it wasn't the best welcome back for him, as he had almost no running today. Not a good start to the weekend, but another PU goes into Pierre's car tonight, and we just plan to do as many laps as we can with him tomorrow to get him up to speed - I know he's fully capable. We're also struggling with the cooling of the car in general, so that was another big focus of our day - this is a track where the ambient pressure is so different to anywhere else, that it's very hard on engine and cooling system, so we were testing lots of things throughout the day to find the optimum going into the race. Even with all of the challenges there are some positives: the pace looks pretty good regarding the low-fuel runs - we're happy where Brendon was - and on the high-fuel the pace and degradation look reasonable. So, all in all, a difficult day, but also with some positives to take from it."

Check out our Friday gallery from Mexico, here.