Nico Rosberg ensured that Mercedes stayed on top of the pile in the final test of F1's pre-season with the quickest time of the day on Sunday in Barcelona.

The German bettered the time set by team-mate Lewis Hamilton on Saturday to give the Brackley-based another boost ahead of the season-opening Australian Grand Prix, with his lap being the best seen across both four-day tests held at Catalunya in recent weeks.

Rosberg's benchmark time came during the morning session on a short-run on the soft Pirelli tyre and was some four-tenths of a second faster than Hamilton had produced a day earlier, although the Briton was on a longer run at the time.

"I'm pleased with our pre-season testing programme," Rosberg admitted. "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. Thanks to the team here at the track and back home at the factory for all their hard work over the last month. I hope it pays off and we can look forward to a positive season ahead together."

Behind the Mercedes, Fernando Alonso also produced a strong performance to become the only other driver to go below 1min 21secs but he would end up three-tenths of a second slower than Rosberg when the chequered flag dropped; neither driver having improved in the afternoon as the majority of teams switched to the harder tyres and higher fuel in the afternoon.

Jenson Button was a second further back in third place for McLaren with the Sauber of Nico Hulkenberg, Kimi Raikkonen's Lotus and Paul di Resta's Force India following closely behind.

"My last day in the car before Melbourne and we made the most of it," di Resta said. "The race distance this afternoon was straightforward and there were no red flags while we were running. The weather was much warmer today and that gives us useful tyre information, which we can compare with the data we have from Adrian's work yesterday in similar conditions."

Raikkonen was one of the few drivers to improve on his return to action but that was down more to the fact that he was forced to sit out most of the morning with a gearbox issue. A run on soft-tyres towards the end of the day were enough to cement his place inside the top six, although the Finn would have hoped for more than the 50 laps he managed to put on the board.

Pastor Maldonado only ran during the morning for Williams ended up seventh ahead of defending champion Sebastian Vettel; the German not worrying about chasing a quick time as he concluded his programme with a best time 2.3secs off the pace.

Valtteri Bottas was ninth for Williams with less than a tenth of a second behind Charles Pic and Jules Bianchi behind.

"I'm pleased with how the last day of testing has gone," Pic said. "We've finished everything we planned for this test and completed 116 laps today, including a race simulation and full pitstops so we've done everything we can to prepare for the start of the season in a couple of weeks.

"It was also important to use the tests to familiarise myself with the whole team. I've really enjoyed working with everyone - there's a good atmosphere inside the team and we're realistic about what we can achieve this year so we'll go into the season with a good spirit and aim to take advantage of anything that comes our way when the races start."

Daniel Ricciardo and Max Chilton completed the 13 drivers to take the track, with the latter returning to action for the afternoon after taking over from Bianchi at the wheel of the Marussia.

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