Ahead of today's opening practice session the air temperature is 29 degrees C, while the track temperature is 38 degrees. Humidity is 81%... it is 18:00 local time.

Being a street circuit it comes as no surprise that the tyre options are soft and supersoft.

There are two DRS zones. The first detection zone is 230m before Turn Five and the first activation point 50m after the same corner. The second detection point is 80m before the apex of Turn 22 and the activation point 45m after the apex of Turn 23.

The big talking point, other than the fight for the title, is the banning of (driver) performance related communications (as from today), with the banning of car performance communications postponed until next year.

As one might expect there are no reserve drivers on duty.

The lights go green and Chilton leads the way, followed by Bottas, Gutierrez, Maldonado, Vergne, Raikkonen and Kvyat.

Five minutes into the session all but Massa and the Mercedes duo – the podium finishers in Monza – have been out. Most of the others have completed one installation lap, a couple two.

"190 kph, fifth gear," Button is advised. Isn't that banned?

As the Briton returns to the pits, Massa and the Mercedes duo are on track.

"My right mirror is moving," do you want me to pit?" asks Rosberg. He is told to continue but the mirror subsequently falls off. He pits.

Hamilton posts the first time of the weekend, the Mercedes driver stopping the clock at 1:52.748. Next time around the Briton improves to 51.934.

As Hamilton continues circulating he is joined by Kvyat, Bianchi, Ericsson, Vettel and Hulkenberg.

As Ericsson posts the second time of the day (57.693), Hamilton dives into the pits having gone quickest in the first two sectors.

Vettel is told to adjust his brake bias, a communication that just a few hours ago was banned.

Rosberg's first flying lap sees the German go second with a 53.613 only to be leapfrogged by countryman Vettel (52.056).

Rosberg improves to 51.640 as Ricciardo goes fourth (52.416), ahead of Bottas, Hulkenberg and Perez.

As Rosberg reports a "big problem on the upshift out of T5", Raikkonen posts 51.269 to go quickest.

As Vettel goes second (51.180) and Vettel third (51.220), Rosberg ups the ante with a 51.031.

A big spin in T5 for Kobayashi after his rear end steps out.

As Grosjean goes off at T2 and teammate Maldonado at T7, Vettel posts 50.411 to go quickest.

Approaching the end of the opening half-hour, during which the drivers have a 'free' set of tyres, all but Button and Gutierrez have posted times. The Mexican has an ERS issue.

At the end of the opening half-hour, it's: Vettel, Alonso, Rosberg, Raikkonen, Ricciardo, Hamilton, Perez, Hulkenberg, Magnussen and Massa.

Rather than the usual lull the follows the opening half-hour, Rosberg is eager to get back to work just moments after handing back his 'free' tyres. The German subsequently posts a 49.205 to go quickest.

As he is given another radio update, Rosberg dismisses the engineer with an; "I don't want to know, I'm OK thank you!" He left off the bit about 'I know what I'm doing'.

Elsewhere, Hamilton goes quickest in the first two sectors, finally crossing the line at 49.178, just 0.027s quicker than his Mercedes teammate.