Nico Rosberg lived up to the promise that he made between the season's first and second Formula One group tests in Valencia and Jerez by putting his Mercedes GP Petronas entry at the top of the times on day one in southern Spain.
The first of eight days of testing at the circuit over the next eleven days was blighted by showers that came and went throughout, leaving the circuit too wet for slick-shod running after the opening hour.
Rosberg began the test for the Mercedes team and just had time to complete a couple of short runs in the dry before the rain arrived and the programme was changed accordingly. Using wet and intermediate tyres, the German gave the MGP W01 its first run-out in inclement conditions, completing 57 laps over the day but relying on a fastest time of 1min 20.927secs which was set in the dry of the early morning. A minor mechanical problem late in the day brought out a red flag that caused the session to be called off slightly ahead of schedule.
“The car felt very good today," Rosberg, who will hand over to team-mate Michael Schumacher on Thursday, commented, "Compared to Valencia, where I was sitting too low - which affected my visibility - and where the set-up wasn't perfect, today I felt really comfortable and I could push, so it was an enjoyable day and a good start to the test for me.
"Our objective here is to learn as much as possible, put miles on the car and engine to check the reliability and to make progress on our set-up work. The rain is a little frustrating, but the car feels good to drive and that's what's important.”
Similarly, Sebastien Buemi's best time of the day was set in that early dry period, but proved good enough to keep the Swiss driver and his Toro Rosso team best of the rest behind Rosberg as the STR5 had its first taste of running in the wet and everyone sampled Bridgestone 2010 tyres. The intermediates are a new tyre, with the front sharing the same narrow width as the dry tyres, while the extreme wets are the same tyres as in 2009 but mounted on narrower rims.
Switching between the two types of tyre, Buemi also evaluated mechanical set-up suited to the wet conditions, as well as carrying out some launch simulations. The car ran reliably all day and the Toro Rosso day ended slightly ahead of the final chequered flag as the entire wet running programme had been completed. Buemi continues driving tomorrow.
Nico Hulkenberg again provided encouragement for the Williams team, posting the third best time of the day as he grew more accustomed to the new FW32, lapping a handful of tenths slower than Buemi, but a similar distance ahead of the Valencia pacesetter Fernando Alonso
Alonso worked mainly on the overall reliability of Ferrari's F10, and on the performance of the two types of tyre available for the wet conditions. The Spaniard covered a total of 88 laps during the day, with a quickest time of 1min 22.895secs, having ventured out for his first run on the dry track with a set of tyres already used in Valencia last week. With the rain arriving, however, the team decided to anticipate some work on the gearbox, originally planned during the lunch break.