Defending F1 World Champion Jenson Button finally lived up to the No.1 adorning the nose of his new McLaren-Mercedes MP4-25 on the fourth and final day of testing at Jerez de la Frontera today – as he concluded the second group session around the southern Spanish circuit on top of the order.
The British star wound up just over two tenths of a second quicker than Robert Kubica aboard the consistently impressive new Renault R30, with star 2009 debutant Kamui Kobayashi again catching the eye by lapping a close third-fastest for Sauber-Ferrari, with all three drivers completing more than 100 laps as – in distinct contrast to earlier in the week – the weather happily remained dry.
Force India F1's Vitantonio Liuzzi was next up half a second further back in fourth, as the Italian focussed his efforts on set-up work and getting a handle on the behaviour of the Mercedes-powered VJM03 with the heavier fuel loads necessitated by the refuelling ban coming into force in the top flight this year.
“Today was a really productive day for us,” the 28-year-old confirmed. “We covered 80 laps without any issues and got through our programme of test items for this week. Everything went pretty well – we worked on understanding the car's performance with different fuel loads and ran through some set-up changes, and the car is responding well.
“We still need to work on the tyres over the longer runs, and will continue this at the next test in Barcelona. Overall I think we can be very satisfied with how this test has gone, and can look forward to another good test next week.”
“A good day to finish the eight days of testing in Jerez,” concurred the ever-improving Silverstone-based squad's chief race engineer Dominic Harlow. “Tonio completed a broad programme of set-up tests, and we are satisfied with what was learned.
“We've made good progress this week, having tidied up some reliability issues and developed our set-up options with the VJM03. The team has begun its race preparation in earnest, and we will head to Barcelona to continue this work over the final test before the first race of 2010.”
Fifth-quickest at the close of play – for the second day in a row – was Nico Rosberg for Mercedes Grand Prix, four tenths down again on Liuzzi. Chassis set-up work over longer runs alongside a tyre comparison programme was the order of the day for the young German, and after some 130 laps the 24-year-old professed himself encouraged by continuing progress.
“We've had a very positive day today,” he affirmed, “and were able to complete a lot of valuable mileage, which is a great way to end the tests here at Jerez. We've made some good progress on our set-up comparisons, and learnt a lot which will be useful to prepare for the final test in Barcelona. Being able to get the laps in dry conditions has been very helpful for me to get used to the car and systems.”