Sebastian Vettel has put Red Bull on top of the timesheets for the opening test day in Barcelona, despite mixed conditions throughout the day. The track was wet for most of the morning, following rain overnight, but it gradually dried to allow some more meaningful running.

Fernando Alonso set a speedy time around midday and as the teams switched to longer runs in the afternoon, it looked like Ferrari would take the headlines. Vettel managed to pip Alonso to the top at the end of the day, beating his time by over a second. With Alonso second in the Ferrari, Jaime Alguersuari finished third in a good show by Toro Rosso.

The lap counts were quite low, most likely due to the conditions, with Force India only completing 26 laps and Vettel, despite being fastest, only lapped the track 37 times. Mercedes, though, had their eyes set on distance:

A good afternoon for Michael and the team with a full race distance simulation... Michael completed 90 laps in total today.

OfficialMGP

In terms of red flags, there were many stoppage periods. Sauber caused one red flag by intentionally allowing Kamui Kobayashi's car to run out of fuel as part of a planned evaluation. Alguersuari and Rubens Barrichello both stopped the running temporarily, with Rubens forced to sit in the garage while the Williams underwent lengthy repairs.

Additionally, Renault had some KERS issues that kept Petrov out of the car until well into the afternoon. He was already sharing duties with Nick Heidfeld, so the pair of them only managed just over 20 laps each, and they finished the day last on the timesheets.