Lewis Hamilton and Mercedes left the competition for dust at the Circuit de Catalunya today as the Briton posted the fastest time of the year at the Spanish track out-pacing his nearest rival by 0.708s.

With weather conditions much improved, as anticipated, today was all about fast times, race simulations, upgrades, driver debuts and exploding wheel nuts.

In the morning, of what is his last day in the W04 before FP1 in Melbourne, Hamilton worked through a series of short runs, using the soft compound tyre. The programme included aerodynamic evaluations alongside different set-up options.

After the lunch break, the focus switched to longer runs looking at aerodynamics and tyre wear. The Englishman completed 117 laps today to take his total pre-season mileage to 1606 miles (2585 kms).

"It was great to have a dry track today," said Hamilton, "as we were able to get through all the test items that we wanted to achieve by the end of my programme. There's still a lot of work ahead of us to get to where we want to be but the team is doing a great job. The guys are working so hard at the factory and here at the track; it's been really nice to get to know everyone in the garage and how they work together over the past few weeks. The reliability, the mileage and the step-by-step improvements that we have achieved during the three tests are all very encouraging.

"Whilst we've been focusing on our own performance, we definitely haven't seen the full potential of our competitors yet," he admitted, "so it's difficult to predict where we might be. I'll be back at the factory next week doing some final preparation work on the simulator and with my engineers, and then it's off to Melbourne for the first race of the new season with my new team."

It was also the final pre-season appearance for Felipe Massa, the Brazilian having been involved in an incident which will be the centre of paddock speculation in the hours and days that follow.

In the morning, the Italian team got through all its planned programme, centred mainly on evaluating some aerodynamic components over short distances, featuring constant speed runs. Massa also began a tyre comparison, which continued through into the afternoon.

After the lunch break, the job list included assessing various set-up changes on the car and some full speed pit stop simulations, including out laps and, for the first time, the team also tried the super soft compound. With less than half an hour remaining, the scarlet car ground to a halt in Turn 10 minus its left front wheel. TV replays appeared to show the wheelnut exploding off of the car as opposed to falling. Initial reports from Ferrari suggest a "problem with the left front upright" however, the investigation is sure to continue into the night... and possibly beyond. Had the failure happened in Turn 9 the end result could have been altogether different.

Adrian Sutil gave a good account of himself at Force India, the German posting the third quickest time of the day, albeit 1.069s off Hamilton's pace. On the other hand, his best time was posted on soft tyres whereas Massa's was on the super-soft compound.