With Mercedes not running on the fourth and final day of the opening test on Friday, Rosberg was therefore driving the W02 for the final time before the car is put into the F1 equivalent of 'retirement' ahead of the new W03's launch in time for the next test at Barcelona. Just before 1pm local time the German became the first driver this week to dip below the 1min18sec mark with his lap of 1:17.613 more than enough to dislodge early pacesetter Romain Grosjean and remain unbeaten thereafter to make it two days at the top in a row for Mercedes. Grosjean, though, will no doubt be pleased with his and the team's performance following his first ever test as an F1 race driver. At the close of play, the Frenchman was still in second place with a time eight tenths of a second clear of the next 2012 car. In the closing minutes his E20 stopped on the track between turns three and four to bring out the day's third red flag, but that may have been explained by Lotus running a fuel-consumption check - and, anyway, by then he already had 117 laps on the board and made an impressive point. The performances of Rosberg and Grosjean came on the day the bookmakers' three favourites for the 2012 Drivers' title - reigning two-time champion Sebastian Vettel, Fernando Alonso and Lewis Hamilton - took to the track in their new respective cars for the first time. Vettel proved the fastest out of the high-profile trio and duly took third place in a best time of 1:19.297, although McLaren's Hamilton was just under two tenths further back in fourth. In their own way, both teams may be happy with their comparative efforts. Ferrari star Alonso, meanwhile, had his first morning in the car disrupted by a hydraulics problem which kept him in the Ferrari garage for the best part of two hours. When he did return to the track, the Spaniard - whose first appearance of the week naturally drew a far larger crowd to the remote Spanish circuit - continued Ferrari's work on data acquisition rather than chasing outright lap times. Like team-mate Felipe Massa in the previous two days, the Spaniard therefore finished in a low-key position on the timesheets - seventh - although by the end of the day he was beginning to put in some consistent times on the medium Pirelli tyres during some longer runs. Day three of the test was also notable for the first two crashes of pre-season - the first of which, for French youngster Jules Bianchi, proved particularly costly for him, Force India and Nico Hulkenberg. Hulkenberg had been due to get his first run in the car this afternoon but reserve driver Bianchi's side-on crash into the barriers on the exit of turn five after just two laps - which brought out the day's first red flag inside the first hour - forced Force India to spend the next few hours working on repairs. They eventually had to admit defeat for the day, however, as they needed replacement parts to be shipped in from their factory in the UK. Hulkenberg will therefore have to wait until Friday to get his preparations for his return to race action in 2012 properly underway. Towards the end of the afternoon's running, another reserve driver - this time new Caterham signing Giedo van der Garde - had a smaller off which required his CT01 to be taken back to the pits on a truck, although his car escaped damage. Meanwhile, Toro Rosso continued their promising start to pre-season with Jean-Eric Vergne taking a competitive fifth place on his debut ahead of fellow young gun Sergio Perez - who was delayed by drivetrain trouble on his Sauber. Bruno Senna made his testing debut for Williams in their new Renault-powered FW34 and while the Brazilian ended up over three seconds off the ultimate pace, the Grove team stressed via Twitter that "there is a lot of working [sic] going on today so it's not all about going for flat out laptimes." More encouragingly for the Brazilian and his team was that the car ran trouble-free for a mammoth 125 laps.

Nico Rosberg of Mercedes during F1 winter testing at the Circuito de Jerez in Spain Nico Rosberg of Mercedes during F1 winter testing at the Circuito de Jerez in Spain. He was fastest on the day. Photograph: Miguel Angel Morenatti/AP Lewis Hamilton and Sebastian Vettel produced almost identical times on the third day of testing in Jerez on Thursday but they were trumped by the Mercedes of Nico Rosberg, even though he was driving last year's car. Romain Grosjean's Lotus was the fastest of the 2012-spec cars, just ahead of Hamilton's McLaren and Vettel's Red Bull. But it was a disappointing day for Fernando Alonso, whose Ferrari looked off the pace, and the team's technical director, Pat Fry, said: "I am not happy with where we are at the moment." Hamilton, though, looked just as cheerful as Button had been the day before as McLaren continued to transform their miserable testing performances of a year ago. The 2008 champion said: "I'm happy to be back and thankful to have a day without any troubles. We did quite a laps compared to last year, so it is all positive so far. "We have not yet figured out the right setup of the car. There are still lots of test items that we have to go through. I would not say the car is more predictable than last year but I would generally say that it feels like an evolution of last year's car, although we have lost the downforce through the corners, but I am sure we will get that back." At the end of last year McLaren were almost as quick as the Red Bulls of Vettel and Mark Webber but they had been playing catch-up all season and it was a particularly disappointing year for Hamilton, who finished fifth in the championship. On Thursday he explained why he had decided to add Didier Coton, the double world champion Mika Hakkinen's manager, to his own management team. "I thought it was a good idea to have," he said. "Me and Simon [Fuller, Hamilton's manager] were looking at ways to strengthen the team a little bit and we wanted to find someone who has more racing experience. "Didier has been a good friend of mine for many years. He has great experience, not just with my team but also in the F1 paddock. It will be strong to have him at the grand prix when I need him. That's what he is there for." But Hamilton did not make any comment about Adrian Sutil, even though he may be forced to go to court as a witness following the German driver's decision to appeal against a conviction following a fight in a Shanghai nightclub last year. Vettel was his usual methodical self, speaking for more than 11 minutes after his run. The double world champion said: "The target is to improve so you have to be open to learn. The idea is to get away in the winter time, take time to reflect and hopefully come back stronger, more prepared and more organised. "We have sat down together and talked through last year and all the things we can improve. Looking from outside it looked almost perfect but there were quite a lot of things on the list, so we will see how we get on. It's quite special this year, with six world champions."