Williams believes that it is in a 'strong midfield position' heading into the 2009 curtain-raising Australian Grand Prix in Melbourne, after pipping McLaren-Mercedes to the honour of the fastest time on the very last day of pre-season testing at Jerez.

Kazuki Nakajima was in the cockpit of the FW31 at the southern Spanish circuit, with the Japanese ace covering just over 100 laps as he focussed his efforts on set-up tuning, aerodynamic work, reliability checks and tyre testing. The 24-year-old professed himself pleased with the former multiple world champions' preparations in the build-up to the beginning of the campaign.

"Firstly, I think we've had a successful run of winter testing," he stated. "We've managed to put a lot of mileage on the car, mainly because we haven't experienced any reliability issues. The team have done a lot of work on the car throughout this process and it's looking quite good, but we will have to wait to see where everyone really is.

"I'm really excited about going to Australia and can't wait to get there now. Many thanks to everyone at the factory for all their hard work, and especially thanks to the guys on the test team."

Team-mate Nico Rosberg echoed Nakajima's sentiments, whilst suggesting moreover that there is 'great potential for development over the year with the new rules'. The inaugural GP2 Series Champion is well aware that this is the season in which he must stake his claim to a long-term future at the front of the grid or else risk being cast into the pile of drivers who ultimately failed to fulfil their potential and never quite made it. The German is hopeful that in Williams' new challenger, he at last has the machine with which to make a real impact.

"Now that we've reached the end of testing, I think that we are probably in a strong midfield position," the 23-year-old revealed, "but we will have to wait until Melbourne to be certain. There's great potential for development over the year with the new rules. If we take the right direction with that development from the outset, it will help us make good steps forward, so we will be pushing hard to make that happen.

"I'd like to thank everyone at the factory for their hard work with the FW31, but particularly the test team for their motivation and drive throughout the winter despite any uncertainties there might be following the in-season test ban that has been put into place. On the back of a difficult season last year, it's been great to see everyone's determination and I am grateful for all their efforts."

"Kazuki was back in the cockpit today, working through last-minute reliability and performance items that required sign-off for Melbourne," added the Grove-based concern's technical director Sam Michael. "We have put over 8,000 kilometres on the FW31 in the last two months and, while there are always areas that require attention, reliability has been good.

"We've also been working hard with Toyota to achieve good reliability on the engine's working range, which has been subject to a reduction in revs but an increase in mileage. Considering the time we've had to do this, the work has gone well.

"At Williams, we are fortunate in that we have an exceptionally strong group of people on our test team who really are the unsung heroes of the sport. Our crew has worked flat-out over the winter, repeatedly taking the FW31 apart and putting it back together, checking everything over and over again to ensure reliability and re-building the car after incidents, all of which is usually done late into the night. We thank them for their tremendous efforts over the past few months and for their contribution to the FW31."

Heikki Kovalainen wound up just shy of half a second adrift of Nakajima at the close of the day - and also of pre-season Formula 1 testing in general. The Finn concluded the on-track proving process of McLaren's troubled MP4-24, productively putting through their paces new components which had arrived overnight from the McLaren Technology Centre.

The 84 tours completed by the 27-year-old took the Woking-based outfit's total mileage with its new machine to 1,655 laps - 693 for Kovalainen, 760 for defending world champion team-mate Lewis Hamilton and 202 for test driver Pedro de la Rosa.

Leading performances - Jerez (19 March):

1. Kazuki Nakajima Williams-Toyota 1min 17.494secs 102 laps
2. Heikki Kovalainen McLaren-Mercedes 1min 17.946secs 84 laps

Track/weather conditions: Sunshine and blue skies. Maximum track temperature 41?C; maximum ambient temp 21?C.

all times unofficial - courtesy of McLaren-Mercedes