Sebastian Vettel and Lewis Hamilton both topped one Practice session apiece in a tightly contested Friday as the action got underway ahead of the season-ending Abu Dhabi Grand Prix.
In the heat of the early afternoon it would be the German who claimed the early initiative for Ferrari, as he beat Hamilton to post the quickest time with 20 minutes to go, but that swapped under the lights in the early evening as the world champion posted a new lap record around the Yas Marina Circuit of 1:37.877s to end the day a tenth-and-a-half in front.
The first practice would be relatively subdued as the hot temperatures were unrepresentative of those that will be seen come qualifying and the race, which both begin shortly before sunset and finish under the lights.
Instead, most teams used the first 90 minutes of running to conduct further initial testing on parts being developed for 2018 with a number running experimental front wings and other aerodynamic parts. The most significant test was being conducted by Kimi Raikkonen as the rear wing of his Ferrari was merely a mounting point for a large aero-rake gathering data on a new diffuser concept.
In the second half, some attention would switch to gaining an understanding of the set-up, with teams able to predict the likely impact of changes later when conditions were more representative and it was then the first signs of a tight battle between the top three teams would emerge.
There would be some difficulties for Daniel Ricciardo, however, as the Australian was only 10th, though with all Renault-powered cars having to be careful with engines it is likely that was the reason for his deficit to the front.
That would change in the evening, however, as, though Hamilton and Vettel continued to lead, it would be Ricciardo in third for Red Bull. Teammate Max Verstappen held that position in the first session too but would slip back to sixth under the lights and seven-tenths slower after going the wrong way with the setup.
In the midfield, a number of key battles remain undecided in the Constructors' Championship but it was Force India's Sergio Perez who led the way in Practice 1 in sixth with the Mexican joined by the second 'pink panther' of Esteban Ocon in the evening as the Silverstone outfit ended as the fourth best team.
Renault is one of the squads looking for a strong result, needing five points to overhaul Toro Rosso in sixth in the Teams' standings and despite the aforementioned measures to ensure engine reliability, it would be Nico Hulkenberg in ninth for the Enstone team come the end of the day after a slow start.
Fernando Alonso was in the top 10 in both sessions for McLaren, as the Spaniard goes in search of a third consecutive points finish to complete an otherwise dismal for the double world champion. His teammate Stoffel Vandoorne is also competitive in 12th but would have his evening compromised by a slide into the run-off area at the penultimate corner, which required him to restart the engine and return to the pits.
Felipe Massa is hoping for a final points result to end his 12-year F1 career and appears in reasonable shape to do so after 9th and 11th in the two practice sessions for Williams. Those two teams are frustrating Haas who need at least three points to move ahead of Renault in the Constructors' but had a day to forget with Romain Grosjean impeding Ricciardo and then spinning in Practice 2, before recovering to the garage after reporting a burning smell.
The American team's issues will be of little satisfaction to Toro Rosso who look very unlikely to add to their points total based on their pace on Friday. Kiwi Brendon Hartley has also seen the unwanted record of grid penalties at every race he has contested continue after a new MGU-H was installed in his car.
Finally, Sauber ended the day 17th and 18th overall with Pascal Wehrlein leading Marcus Ericsson in both sessions in what could well be the German's last F1 weekend at least until 2019.
