After Lewis Hamilton yesterday highlighted the forward steps taken by Mercedes over the winter months, team-mate Nico Rosberg reinforced the message by setting the fastest time of the final day of pre-season testing and the fastest time of the second four-day spell the Circuit de Catalunya.

Rosberg’s time of 1:20.130 was set in the morning as the lunch break neared on a single-lap run. As with Hamilton’s lap yesterday the time stood until the end of the day as teams focused on longer runs and race simulations in the afternoon.

"I have the general feeling that we are in a better position than in the second half of last year but this is testing not racing."
Nico Rosberg

Mercedes had more reason to happy, as allied to Rosberg’s pace was impressive reliability. The German completed 131 laps on the final day, the largest tally of any driver.

Afterwards, Rosberg admitted that he feels the team has improved greatly on the car with which it ended last season.

“I’m pleased with our pre-season testing programme,” he said. “We have achieved a lot of mileage and I can feel that the balance of the car is good. I have the general feeling that we are in a better position than in the second half of last year but this is testing not racing, of course. The conditions in the first race will be completely different to here as it will be much hotter in Melbourne and Sepang so we need to wait and see.”

The only other driver to go under the one minute, 20-second mark today was Ferrari’s Fernando Alonso. The Spaniard’s lap of 1:20.494, recorded shortly after Rosberg’s, was also on the soft tyre. Jenson Button was third for McLaren with a time of 1:21.44, though the Briton’s time was set on the unmarked tyre Pirelli brought to this test, believed to be a medium compound.

While the top three are likely to feel satisfied with their final efforts in Barcelona, one potential front-runner who left the circuit unimpressed by the final week’s work was defending champion Sebastian Vettel.

The Red Bull Racing driver got through 100 laps on his way to eighth place on the last test outing at the wheel of the RB9 but afterwards Vettel said testing had been inconclusive due to the behaviour of Pirelli’s tyres.

"We’ve never had a winter that was less conclusive that this one. All the teams were linked in to what the tyres could do and at times it was extremely difficult to read the set-up changes."
Sebastian Vettel

“I think we’ve never had a winter that was less conclusive that this one,” he said. “If you sum up all three tests I think all the teams were linked in to what the tyres could do and at times it was extremely difficult to read the set-up changes and find a direction because the tyres were always pretty challenging. The tyres last, if anything, one lap, so it’s impossible to read the pace of the car and to make out who is favourite is not easy.

“The last two days weren’t as good as we expected but we still have time before the first race,” he added. “I think it’s extremely difficult to pinpoint the exact area [in which we need improve] as the tyres are not consistent enough. The last two days were pretty good in terms of weather, it wasn’t cold and the asphalt was quite warm but the tyres were still poor. We need to look into the data to understand what awaits us in Melbourne. But lap times are not important and where we are now on the time sheet is not that important.”

Kimi Raikkonen, returning from the illness that sidelined him from Saturday’s running also had an unhappy final day, with a morning gearbox problems restricting the Finn to garage for most of the opening phase of running. Once he did take to the track, Raikkonen climbed the order to end the day with the fifth-fastest time, behind Sauber’s Nico Hulkenberg.

“I was sick yesterday and the car was sick this morning,” he said. “It’s not what you want, but you go testing to find out if there are any problems with the car. For sure, we haven’t completed all the laps we wanted during pre-season, but that is often the case. Personally, I felt much better today and I was fine driving.”

Lotus Technical Director James Allison was more forthright, saying the day’s running was a mirror of the team’s test programme whole programme in Barcelona.

“Today was something like this entire test in microcosm; we spent too much of the day in the garage, but when we did get out on track we made good progress,” he said.  “A definite positive is that we are not finding it difficult to be on the pace. Today’s gearbox problem was the same as we experienced previously but we’re confident we have a solution and are not concerned about it causing us any issues in Melbourne.”

Paul Di Resta ended Force India’s test with sixth place and the Scot was followed by Williams Pastor Maldonado and Vettel. Ninth place went to second Williams driver Valtteri Bottas, while a good day for Caterham saw Charles Pic complete 116 laps and claim the day’s 10th-quickest time. The remaining spots on the timesheet were filled by Marussia’s Jules Bianchi, Toro Rosso’s Daniel Ricciardo and Max Chilton, who took over from Bianchi at the wheel of Marussia’s MR02 in the afternoon.

Barcelona test times – Day Four

1 Nico Rosberg Mercedes 1m 20.130s

2 Fernando Alonso Ferrari 1m 20.494s

3 Jenson Button McLaren 1m 21.444s

4 Nico Hulkenberg Sauber 1m 21.541s 118

5 Kimi Raikkonen Lotus 1m 21.658s 50

6 Paul di Resta Force India 1m 21.664s 112

7 Pastor Maldonado Williams 1m 22.415s 42

8 Sebastian Vettel Red Bull Racing 1m 22.514s 100

9 Valtteri Bottas Williams 1m 22.524s 31

10 Charles Pic Caterham 1m 23.115s 116

11 Jules Bianchi Marussia 1m 23.167s 62

12 Daniel Ricciardo Scuderia Toro Rosso 1m 23.628s 91

13 Max Chilton Marussia 1m 24.103s 49