Barcelona Day 4: Rosberg quickest as Mercedes blitz rivals again

Who is showboating? Who is sandbagging? Big questions at the end of the final day of Formula 1 preseason testing in Barcelona, but whatever the case there is no taking away the fact that Mercedes, for a second day running, showed hugely impressive pace with Nico Rosberg topping the timing sheets with the fastest time of all eight days at Circuit de Catalunya. Next stop... Melbourne!

Rosberg's best time of 1.20.130 was set with soft Pirelli tyres bolted to the W04, and was one of several laps in the 80 seconds zone during the course of the day by the German. The time was also 0.428 seconds up on Lewis Hamilton's best in the same cockpit 24 hours earlier.

Rosberg told Sky Sports, "As we all know, we have to be very careful with the results of testing because you just don't know what other people are doing and we know for a fact that our competitors haven't shown their potential yet. So we need to be very careful."

Nico Rosberg Mercedes W04

"What I can say is that we have made progress and I am pleased with how the winter has gone. Everything has gone to plan and the reliability has been sorted out. Pleased is probably the best word, but we need to wait and see for Melbourne."

"For sure, I can see that back in the factory things are working well and everything has come together at testing, but performance-wise we still need to wait for Melbourne to see where we are," concluded the German.

Next up and also showing a good turn of pace was the Ferrari F138 in the hands of Fernando Alonso, who would give the Maranello squad reason to smile as he too dipped in to the 80 seconds zone regularly, on his hot lap runs, on Pirelli soft tyres. The F139 was not as effective on the super softs which the Spaniard tried late in the day.

Fernando Alonso comes in for a pit stop in the Ferrari F138

When the chequered flag waved to end the action he was 0.364 down on Rosberg's best. The pair having provided intriguing morning entertainment as they traded blows - make that times - at the top of the timing screens.

Jenson Button was next best, albeit 1.314 seconds adrift of the top time in the McLaren MP4-28. The 2009 world champion spent most of his track time on harder compounds but did go out on a set of disguised Pirelli tyres - probably soft compound - late in the day.

Notably the top three did 363 laps of the Spanish Grand Prix venue during the course of the final day, equivalent to five and a half grand prix distances.

The Sauber C32 continued to impress in the hands of Nico Hulkenberg, who ended fourth fastest with 118 laps to his credit.

Kimi Raikkonen Lotus E21

Returning to action after a dose of food poisoning, which kept him out of the Lotus E21 cockpit the previous day, was Kimi Raikkonen. Adding frustration to the Iceman's final preseason test in Barcelona was the fact that he was forced to sit out most of the morning thanks to a gearbox problem. When he finally got out on track, he nevertheless managed to rack up 50 laps on the way to setting the fifth best time.

After a two day layoff Paul di Resta was back on duty in the Force India VJM06, ending his day with 112 laps on his chart and the sixth best time.

Williams again went against the norm by splitting the day's duties in the FW35 between their two drivers. Pastor Maldonado doing the morning shift and setting the seventh best time, before Valtteri Bottas took over for the afternoon stint and ending ninth fastest. The pair racked up 73 laps in the process.

Sebastian Vettel Red Bull RB9

Splitting the Williams duo, and eighth on the timing sheets was Sebastian Vettel in the Red Bull RB9. He managed 100 laps but was 2.384 seconds down on the day's top time suggesting that the world champions are keeping their powder dry for when it matters.

Charles Pic was tenth quickest in the Caterham CT03, followed by Jules Bianchi in the Marussia MR02, Daniel Ricciardo in the Toro Rosso STR8 and Marussia's Max Chilton slowest of all.

There were no stoppages during the final day of testing.

Invariably the question of pecking order arises, particularly with preseason testing now done and dusted. It would be a tough call to make on the evidence of what was seen in Barcelona over the past four days.

Charles Pic in the Caterham CT03 makes a pit stop

However it can be assumed tat Red Bull have a potent weapon in their RB9, with Ferrari and McLaren likely to be right in there, although the Woking squad may have issues with the new Pirelli tyres and how to extract the best from them.

Lotus and Mercedes seem to have made progress, especially the Silver Arrows who were mighty on the final two days in Spain, with Force India and particularly Williams the underdogs who may be capable of an upset.

The one sure thing is that it is a lot tighter up at the front - concertina style - and in all likelihood the top four or five teams are within a quarter second, thus setting the scene for another epic season.