History was made today, as Pirelli returned to Formula One racing in the United States for the first time since 1990, when the Italian tyres were last seen at the United States Grand Prix in Phoenix, Arizona. The P Zero Silver hard tyres and P Zero White medium were used in free practice at Austin, as the teams got their very first chance to familiarise themselves with the brand-new circuit. In order to allow them to maximise their running, Pirelli brought an additional set of the hard compound tyres for today's two free practice sessions only, enabling the drivers to complete more laps than they would usually on a Friday.

With the teams relying only on simulation data up to now, there was plenty of work for them to do to analyse tyre behaviour on each compound under a wide variety of race conditions. Primarily, the work consisted of understanding the amount of wear and degradation on both of the compounds with full and empty fuel loads, in order to replicate the different qualifying and race conditions that will be seen over the course of the weekend. The teams also had the opportunity to try out different set-ups and see how they interacted with the tyres on this unique new circuit.

Weather conditions in Texas remained dry throughout the day but rather cooler than expected, with ambient temperatures in the region of 20 degrees centigrade and track temperatures of 30 degrees during the second free practice session in the afternoon, held at the same time that qualifying and the race will take place. As usual, the teams concentrated just on the hard tyre in the morning, with the emphasis on familiarisation and initial set-up work.

In the more representative conditions of the afternoon, the teams also moved on to the medium compound and more detailed tyre assessment took place that will provide crucial information when it comes to formulating race strategy for Sunday. With the asphalt in Austin being brand new, there was a high degree of track evolution resulting in the lap times getting quicker and quicker as more rubber was laid down - and this will continue to be the case throughout the rest of the weekend.

The fastest time of the day was 1:37.718, set by Red Bull driver Sebastian Vettel on the medium tyre in the second session. In the morning, Vettel was also quickest with a time of 1:38.125 on the hard tyre.

Paul Hembery: "Today was all about familiarisation for the teams on what is the only brand new track of the year. With weather conditions being cooler than expected, the initial data suggests that both wear and degradation is very low on both compounds, which leads us to think that we will see just one stop on Sunday, but we will have to look at all the numbers in more detail tonight to have a clearer picture. Our data simulation work has proved to be extremely accurate, with both the compounds performing exactly as we expected, although we also have to take into account the high degree of track evolution that could certainly affect the strategy on Sunday. We're seeing a performance gap of around half a second per lap between the two compounds, which gives the teams plenty of scope to try to gain an advantage through the timing of their pit stops. Nonetheless, as this is a completely new circuit with a number of potentially unknown factors, we deliberately opted for a conservative tyre choice here."

Sets used overall:

Hard: 71
Medium: 24

Longest runs per compound:

Hard: 19 (Kobayashi)
Medium: 14 (Grosjean)

Pirelli fact of the day:

When Pirelli last raced in Formula One in the United States, at the 1990 Phoenix Grand Prix, it supplied just three small teams: Brabham, Minardi and Zakspeed. Minardi, in particular, was a giant-killer armed with Pirelli's rapid qualifying tyres: Pierluigi Martini put his car in an astonishing second on the grid for the US GP, less than seven-hundredths of a second off Gerhard Berger's pole time for Ferrari.

Check out our Friday gallery, here.