As the lightning flashed and the rain pounded the ground, Ferrari Communications Manager, Luca Colajanni, was adamant, his team would be in action today.

Sure enough, not too long after the designated start time for today's session, Felipe Massa fired up his Ferrari and went out for an exploration lap. As the scarlet car made its way around the Autodromo Nazionale, to the frustration of the man fans present, the rain fell even harder.

At one stage a couple of the garages showed worrying signs of flooding, and it was feared that even the extra test day now allotted for Friday might have be called off. As it happened, eventually the rain stopped, and shortly after 13:00 [local time] the session finally got underway, much to the delight of the ever patient fans and frustrated drivers and engineers.

Fernando Alonso left the McLaren garage for the first time shortly after 13:30, with the circuit still very wet. However, it was soon too dry for wet tyres in general, but remained damp in places, such as through the Lesmos. As a result running on dry tyres was compromised to an extent, so work focused on long distance runs. Towards the end of the day, although the track did not fully dry, the Spaniard spent more time looking at set-up for Monza.

In the couple of hours that the session ran, the World Champion completed 51 laps, posting a best time of 1:23.490.

With session continuing tomorrow, Pedro de la Rosa has been drafted in to take over from his fellow Spaniard.

Robert Kubica completed several laps in the wet in order to gather data using standard wet tyres. After the track had dried out, the Pole worked on the set-up of the car. An unspecified technical problem brought his session to an early close after 48 laps.

It was David Coulthard's first day on track and he continued with tyre evaluation and also carried out a repeat of some aero testing done earlier in the week, partly to get more data and partly to validate Mark Webber's impressions. Like its rivals, the Austrian team had just half a day on track, but it was productive.

Fourth quickest was Massa, who suffered a failure as he left his garage near the end of the session. The Brazilian worked principally on set-up changes in preparation for next week's Grand Prix, as well as on developments of aerodynamic solutions aimed specifically at this track.

Tonio Liuzzi, who took over from Sebastian Vettel, began on intermediate tyres and then switched to dry as he focussed on next week. The Italian will continue here tomorrow.

Like Massa, Honda's Jenson Button completed one installation lap before returning to the safety of the garage for the remainder of the morning session.

Once the afternoon session got underway, the Englishman was able to go out on the wet tyres, before switching to the dry tyres for the first time shortly afterwards. He completed some initial set-up work before running through a tyre evaluation with the tyre options for next week´s race.

Nico Rosberg ended the day seventh fastest, posting a best time 1.49s off Alonso's pace. In the "limited window" the weather allowed, the German continued with set-up work for next week.

Giancarlo Fisichella completed an installation lap shortly after 09:30, but like Massa and Button, the Italian discovered the circuit conditions were unsafe.

When the session resumed, Fisichella focused on a set-up programme, as he fine-tuned the car's handling in drying and then fully dry conditions. By the end of the day, the Italian had completed 72 laps, setting a fastest time of 1:25.069 which put him eighth in the final standings.

Although the poor weather meant he was unable to complete a full programme, the French team believes the useful data he collected will provide a good starting point for his work in Friday practice next week.

Having completed its major test items, and in order to save mileage for testing later in the year, the French Team has opted not to prolong the test by an extra day, and will return to base this evening.

"Even though we did less running than planned, I am quite pleased with the day," said Fisichella. "It was an important test, just one week before my home race, and all the more so because this is a very unusual circuit in terms of the high speeds, and how we use the brakes. I ran in wet and dry conditions, and I think we made good progress ahead of next week's race.

"The weather conditions were just too bad to run in this morning," said Christian Silk. "But by the end of the day, the engineers were pretty pleased with the car balance, which is promising ahead of next week's Grand Prix. We collected a lot of data during these three days of testing, and our performance engineers will now begin analysing them to put us in the best possible position for next weekend."