Ahead of today's opening session the air temperature is 22 degrees C, whilst the track temperature is 32 degrees. It's also quite windy.

The big news, of course, is that Fernando Alonso will play no part in the weekend, the Spaniard having suffered a couple of cracked ribs in that horrific Melbourne crash.

Which means that McLaren understudy Stoffel Vandoorne gets his chance to shine, the Belgian youngster having flown back early from Japan where he was taking part in pre-season testing for Super Formula.

Also making his F1 (race weekend) debut is Force India reserve Alfonso Celis who will be at the wheel of Sergio Perez' car. The Mexican is due to take part in seven FP1 sessions this year.

Tyre options are the same as in Melbourne, supersoft, soft and medium however, in a curious move the Ferrari drivers have several (three) sets of the medium each whilst the Mercedes duo have opted for one set apiece instead looking to the softs.

As a point of interest, Vandoorne has the race number 47 whilst Celis has been given 34.

Incidentally, Vandoorne has won here on three occasions, in GP2.

The lights go green and Gutierrez, who has been waiting patiently at the end of the pitlane for some time, leads the way, followed by Wehrlein, Verstappen, Celis and Magnussen.

Soon all but the Mercedes duo have been out, the drivers using a mixture of soft and mediums.

Vandoorne is one of the eager beavers, his McLaren sporting a wide array of aero sensors.

Ten minutes in and the Mercedes duo finally appear.

Fifteen minutes in and Wehrlein posts the first time of the weekend, the German crossing the line at 1:39.743. As the Manor driver improves to 38.292, Ricciardo leapfrogs him with a 36.256.

In the McLaren garage, Ron Dennis offers words of encouragement to Vandoorne, whilst Alonso is there to give moral support.

As Kvyat and Ericsson take their places on the timesheets, Rosberg heads out again. The German subsequently posts 33.592 to go quickest. Moments later teammate Hamilton posts 33.673 to go second. Both are on softs.

"More cars on track now as the surface rubbers in," confirms Pirelli. "But conditions in FP2 will be very different, so this session is not the most useful."

On his first flying lap, Vandoorne is caught out by the tailwind at T11 locks-up and runs wide. Consequently he can only manage 39.082. On the other hand, teammate Button goes third with a 35.440.

Hulkenberg (35.534) improves to fourth, ahead of Bottas, Ricciardo and Kvyat.

Raikkonen heads down the pitlane on mediums, his teammate following shortly after.

Vandoorne improves to eleventh with a 36.893 as Gutierrez slows on the final straight, the Mexican appearing to have a problem.

Raikkonen goes seventh with a 35.870, with Vettel going eighth (35.914) moments later.

His issue seemingly rectified, Gutierrez continues, meaning that all 22 drivers on track.

Vettel reveals that his drink bottle is leaking on to his leg. Elsewhere, a big, big lock-up for Massa. A big lock-up for Grosjean also, the Frenchman currently ninth behind the two Ferraris.

Forty minutes in, and as the drivers prepare to hand back their first set of tyres, it's: Rosberg, Hamilton, Button, Hulkenberg, Bottas, Verstappen, Raikkonen, Vettel, Grosjean and Sainz. The ten are covered by 2.493.

The track falls silent.

After several minutes of inactivity, except in the garages where the mechanics work furiously, Magnussen heads out and gets the session underway again. He is followed by Vandoorne.

PBs in all three sectors see Magnussen (softs) improve to fourth. Vandoorne improves to fourteenth with a 36.392, the Belgian having performed a number of practice pit stops.

Celis improves to twentieth with a 37.735, ahead of the Manor duo.

Ricciardo (softs) posts 34.461 to go third, albeit 0.869s off Rosberg's pace.

Kvyat and Hulkenberg improve to fourth and fifth, demoting Button to sixth in the process.

Palmer complains of understeer especially in the high-speed sections of the track. The Briton is currently nineteenth, whilst teammate Magnussen is seventh.

The Sauber duo go sixth and seventh, Grosjean (35.000) the quicker of the pair.

Celis improves to twentieth (37.287) but remains well off the pace of teammate Hulkenberg.

Ericsson improves by almost 2s to go eleventh, as the Mercedes duo raise the benchmark ever higher, Rosberg posting a 32.294 and Hamilton 32.799, leaving (third placed) Ricciardo 2.167s in their wake.

TV cameras pick up the fuel flap falling (flying away) from Grosjean's Haas.

With fifteen minutes remaining, the Ferraris are on track, Raikkonen of softs and Vettel still on the mediums. Vettel improves to ninth (35.073) whilst Raikkonen posts 34.128 to go third, 1.834s off Rosberg's pace.

Almost unnoticed, the Toro Rosso duo have gone seventh and eighth, Sainz (34.793), the quicker of the two.

With three minutes remaining, a number of drivers head into the pitlane, their morning's work at an end. As Pirelli said, as this session is earlier than any others this weekend it is pretty much redundant.

A late problem for Magnussen who appears to be stuck in gear. "Take it easy, take it easy," he is told.

A lacklustre session with Mercedes still the class of the field, but good to see fourth to twelfth covered by just one second.

Rosberg is quickest, ahead of Hamilton, Raikkonen, Ricciardo, Kvyat, Hulkenberg, Sainz, Verstappen, Grosjean and Massa.

Vettel is eleventh, ahead of Bottas, Gutierrez, Button, Magnussen, Ericsson, Wehrlein, Vandoorne, Nasr, Palmer, Celis and Haryanto.

Check out our Friday gallery, here.