Formula One drivers took to the track at night for the first time this year, during the first two free practice sessions for the Singapore Grand Prix. With the race being one of the most specialised and tough encounters of the year, the task of collecting data on both the P Zero Yellow soft and P Zero Red supersoft tyres was more important than ever on different fuel loads.

The cars will start the race with the heaviest fuel load of the year - up to 160 kilogrammes - and keep going for nearly two hours, meaning that the balance of the car alters drastically over the course of the grand prix. This has a big effect on the way that each car uses its tyres, so today was all about running for as long as possible on Pirelli's two softest (and fastest) compounds, nominated for this weekend. At the end of the second free practice session most of the front-running teams concentrated on high fuel loads with the supersoft tyre: the configuration that they are likely to start the race with.

Unlike most circuits, ambient and track temperatures remained the same: in the region of 28 degrees centigrade throughout the second session, where Red Bull driver Sebastian Vettel set the fastest time of the weekend so far with a benchmark of 1m48.340s on the supersoft. Vettel went more than three-tenths of a second quicker than the runner-up in the second session, McLaren's Jenson Button.

High ambient temperatures and constant humidity in Singapore lead to a significant degree of thermal degradation, so the art of managing the tyres consists of bringing them up to temperature quickly and then maintaining them within the correct operating window without overheating the rubber, particularly in the many traction and braking areas.

Before the start of the first free practice session there was some heavy rain, which left the circuit damp when the cars first took to the track. Most drivers went out on Pirelli's Cinturato Green intermediate tyres (with Ferrari's Fernando Alonso quickest of them) while some drivers also used the Cinturato Blue full wet tyre to assess the amount of water on the track. Subsequently, the circuit dried enough for the P Zero Yellow soft tyres to come out. Nobody used the supersoft tyres in the first session, with Vettel going fastest on a time of 1m50.566s, less than a tenth of a second faster than McLaren's Lewis Hamilton.

The P Zero Red supersoft tyre made its first appearance of the weekend just under half an hour into the second free practice session, on the Toro Rosso of Jean-Eric Vergne, after all the drivers started on the soft tyre before progressively moving onto the supersoft. The session was interrupted briefly halfway through for the Williams of Bruno Senna to be retrieved after it hit a barrier at turn 19.

Paul Hembery: "As always, Singapore has got off to a spectacular start, with the complexity of this race being added to by a damp surface at the beginning of the first free practice session. Nonetheless we saw a lot of running over the course of the evening, with plenty of data accumulated on a wide variety of fuel loads. From what we can see so far we would expect between two and three pit stops during the race, but a lot will depend on safety cars, which have traditionally been a factor in Singapore, as well as driving styles. The time difference between the soft and supersoft is around 1.5 seconds per lap, while the degradation per lap is around 0.3 seconds for the supersoft and 0.1 seconds for the soft. This opens up lots of different possibilities in terms of strategy. We've also seen a number of upgrades from teams here, which will only add to the closeness of the competition. Some teams might try something different when it comes to strategy such as starting on the harder tyre, for example, in order to run a longer first stint on heavy fuel. Already, we've seen lots of different programmes during free practice, which suggests that the teams are keeping a very open mind when it comes to their tactics."

Sets used overall:

Soft: 50
Supersoft: 24
Intermediate: 22
Wet: 7

Highest number of laps per compound:

Soft: 24
Supersoft: 19
Intermediate: 9
Wet: 2

Longest runs per compound:

Soft: 14 (Rosberg)
Supersoft: 14 (Di Resta, Hamilton, Hulkenberg)
Intermediate: 8 (Vettel)

Facts of the day:

The track asphalt in Singapore, made up of the city streets, has been resurfaced since last year between turns five and seven as well as on the approach to and the apex of turn 13. The new tarmac offers better grip, as well as revised kerbs that are designed to be kinder to the cars.

Singapore is well known as an endurance test for the drivers as well as the cars and tyres. The amount of fluid lost during the hot and humid race means that the drivers lose between two and three kilograms over the course of the race: nearly a third of the weight of a Formula One wheel and tyre.

Check out our Practice gallery, here.