Ferrari's Felipe Massa and Kimi Raikkonen topped the timesheets on the first day of testing at the Sakhir circuit in Bahrain. 16 drivers representing 9 teams were in action, in almost ideal conditions and temperatures reaching 23 degrees.

For Ferrari, Raikkonen and Massa got started on an intensive technical programme, built around endurance, set-up and electronics testing. Between them the Maranello drivers completed 133 trouble-free laps, posting best times around 0.2s faster than the nearest opposition.

Jenson Button and Rubens Barrichello were in action for Honda, at a time when the Englishman is admitting that the Japanese team is struggling for pace. Therefore today's result - he finished third fastest - will lift the mood in the team, though a technical (throttle) problem in the morning cost track time.

Button gave the new chassis (04) its first outing this morning. After some initial set-up work, he completed an intensive aero programme, alongside some new tyre runs. Meanwhile, Barrichello concentrated on finding a good set-up, before completing long tyre runs over a race distance as he evaluated the two tyre tyres supplied by Bridgestone.

McLaren had Lewis Hamilton and Pedro de la Rosa on duty, as the Woking team ran the Melbourne spec of the MP4-22 for the first time. Both drivers focussed on final sign-offs on elements of the MP4-22 package, such as software.

It was another good day for BMW, which was represented by Nick Heidfeld and Sebastian Vettel. Both drivers started the day by working on a baseline setup.

Unfortunately, Heidfeld could not complete his programme due to unspecified technical problems, though Vettel's day was trouble free. The youngster's programme in the afternoon included tyre comparisons, testing new aero parts and work on the traction control.

Tomorrow and Saturday Robert Kubica will take over from Vettel. In the morning the Pole has to set up his car as it will be his first day of testing in Bahrain. For Heidfeld aerodynamic tests are scheduled, with both drivers carrying out a race simulation in the afternoon.

The hot weather allowed Ralf Schumacher and Jarno Trulli the opportunity to try out the new Bridgestone tyres for the first time in the kind of conditions expected at many races this year. The team also had new aerodynamic parts on the car for evaluation.

The Italian's day had barely started before a gearbox control issue forced him back into the garage for lengthy repairs while Schumacher took advantage of the near-perfect conditions to register some early laps. Unfortunately, the German was also halted as lunchtime approached when a clutch needed repairing, but when the green flags waved to start the afternoon session, both drivers were back on track. Minor repairs caused further delays and the team is now looking forward to a more positive second day.

"This was definitely not the first day we imagined here," admitted Chief Engineers, Dieter Gass. "We faced quite a few issues during the day which prevented us running through our programme smoothly. On Ralf's car after trouble with the clutch we had a problem with the differential control which investigated throughout the afternoon. With Jarno's car we had a gearbox control issue in the morning which cost us a lot of time. Overall unfortunately we couldn't do a lot of work on the car. We will have to continue with our programme and we are still optimistic as there are nearly two weeks of testing left here."

Tenth quickest was Anthony Davidson in the Super Aguri, the Englishman undertaking all testing duties for the team during the one-car, three-day programme.