Austria test, Day One: Pascal Wehrlein fastest as rain plays havoc

The opening day of the post-Austrian GP test developed into something akin to an F1 marathon after a long morning rain delay pushed the conclusion of the session all the way to mid-evening at the Red Bull Ring.

However, despite the delays and interruptions as the Styrian weather delivered by far the worst it has had to offer since F1 arrived in the Austrian mountains last week, the result at the head of the timesheet was unchanged from the race weekend – Mercedes wound up fastest.

But it was neither Sunday’s race winner Nico Rosberg nor Lewis Hamilton, absent from this two-day test, who occupied top spot on this occasion as the team’s German reserve driver Pascal Wehrlein returned to the W06 to set the pace on a 1:11.005.  Rosberg had been due to drive the car on Tuesday, but Mercedes followed Red Bull and McLaren's leads in shuffling their driver pack owing to the expected poor conditions.

Wehrlein still completed 67 laps despite having to wait until after the lunchbreak to take to the track after the morning deluge produced a red-flag period of over four hours. With so much crucial running time lost for the field in what is the second and final in-season test of 2015, officials opted to lengthen the day by two hours once conditions improved in the afternoon to enable more useful track time.

While the undulating track was naturally initially very wet, drivers were able to work their way down from full wet, to intermediate and then finally slick tyres as the elongated session progressed with lap times tumbling as a result.

Wehrlein’s eventual 1:11 lap, over two seconds slower than Hamilton’s pole from Saturday, on the supersoft tyres proved 0.187s quicker than Esteban Ocon, another Mercedes-backed youngster. The 18-year-old Frenchman was running for Force India as the Silverstone-based team gave a debut run-out to a number of new aerodynamic upgrades which will form part of the 'B-spec' car they are introducing at next weekend’s British GP.

Max Verstappen, only one of two race drivers in the Day One field alongside Lotus's Romain Grosjean, was third for Toro Rosso after again running strongly in the initial wet conditions of the afternoon. The Toro Rosso rookie completed the day’s most laps – 97 – to finish three tenths back on the Mercedes.

Ferrari, meanwhile, gave an F1 test debut to GP3 driver Antonio Fuoco, but while the teenage Italian finished fourth on the timesheet, he blotted his copybook with an afternoon spin into the Turn One barriers which curtailed the rest of his day after 71 laps.

Grosjean was fifth-fastest for Lotus, ahead of Red Bull junior Pierre Gasly and Sauber reserve Raffaele Marciello who was delayed in the team's garage until the final third of the day by an electrical problem.

Runaway GP2 title leader Stoffel Vandoorne was given another chance to impress McLaren's hierarchy and the 23-year-old Belgian was actually only one of two drivers, the other being Fuoco, who briefly sampled the track in the heavy rain of the morning before the session was red-flagged.

But while the 76 laps completed by Vandoorne will further aid his development as a driver, they were arguably even more important for a McLaren-Honda partnership which has continued to be beset by both unreliability and underperformance.

Meanwhile, in what was her third outing in the FW37 this year, Susie Wolff rounded out the nine runners as Williams provided the technical talking point of the day via the appearance of an interesting-looking winglet on the floor in front of the car's rear wheels. Amid increasingly tight regulations over that area of the car, it remains to be seen whether it is a part the Grove team intend to race or plays in to a wider aerodynamic evaluation. 

Austria test, Day One timesheet:

1. Pascal Wehrlein, Mercedes, 1:11.005, 67 laps

2. Esteban Ocon, Force India, 1:11.192, 76 laps

3. Max Verstappen, Toro Rosso, 1:11.328, 97 laps

4. Antonio Fuoco, Ferrari, 1:11.331, 71 laps

5. Romain Grosjean, Lotus, 1:11.509, 45 laps

6. Pierre Gasly, Red Bull, 1:11.757, 80 laps

7. Raffaele Marciello, Sauber, 1:11.826, 53 laps

8. Stoffel Vandoorne, McLaren, 1:12.530, 76 laps

9. Susie Wolff, Williams, 1:13.248, 39 laps