Nico Rosberg and Mercedes in class of one in Bahrain

Nico Rosberg was in a class of his own on Saturday in Bahrain as the second pre-season wrapped up.
The German put his team-mate's time of 1:34.2 from Friday in the shade early as he beat it not once but twice in the first two hours before ending the day on top with a best of 1:33.283 just a second off his own pole time at the same circuit last year.
After lighting up the timings, Rosberg then set off on a full race simulation completing 89 laps on the day. It wasn’t completely plain sailing though for Mercedes as his day was cut an hour short with a car failure.
As for McLaren, Jenson Button remained in the car for the final day and the 2009 champion had a near identical program as on Friday.
He, like Rosberg, completed his best time of 1:34.957 on lower fuel in the first few hours before concentrating on longer runs for much of the afternoon managing 66 laps by the close.
Once again breaking the Mercedes-powered stranglehold at the top of the timings was Ferrari as Kimi Raikkonen made up for time lost following telemetry issues on Friday closing on the day with 81 laps and the third best time albeit nearly three and a half seconds slower than Rosberg.
The day wasn’t perfect however after Raikkonen lost control of the F14-T exiting turn four causing the final red flag of the day ad bringing a slightly premature end to proceedings.
Early news on Saturday in the desert was confirmation of GP2 driver Felipe Nasr as reserve driver at Williams, the Brazilian jumped straight into the FW36 and had a successful debut with a second best tally of 87 laps and finishing fourth on the timings.
The final day was also a better day for the Lotus team who ended their first official week of testing with Pastor Maldonado taking fifth in the E22 over five seconds down on the Mercedes. The time was largely irrelevant however as it was the 58 laps, or just over a full race distance at the Sakhir circuit, that will make for happier faces back in Enstone after a difficult week.
As one team finished on a high other’s ended on a low as Force India, with Sergio Perez behind the wheel, managed just 100km on Saturday before being cut short by what was described as ‘power train’ issues, however it is understood the new 8-speed gearbox is the likely culprit.
It was a similar story at both Red Bull teams as Daniel Ricciardo and Jean-Eric Vergne again failed to make it over 20 laps each.
The Australian was the faster of the two after he had gone sub 1:40 on the day but both will be hoping for much improved reliability and speed at the final test next week.
Caterham split the running between both their drivers on the final day but, unlike earlier in the week, had a disappointing Saturday managing just 21 laps between them and finishing last of those to set a time.
Sauber’s Adrian Sutil failed to set a time as an issue with the monocoque caused a complete rebuild of the C33 which took up much of the day before the late flurry of red flags limited the German to seven laps, while Marussia also had issues and instead switched focus to preparing for next week’s test at the same venue by shaking down some new parts.
There is absolutely no doubt looking back over the first four days in Bahrain that the story remains one of apparent Mercedes superiority both in speed and reliability with Renault, and notably Red Bull, well off the pace and still struggling to simply string a good number of laps together.
The big question is Ferrari. The Italian team did not set any blistering times during the week yet were consistently in the top three or four and completed a good number of laps, certainly the Scuderia are keeping the cards close to their chests but will they show any more of their hand at the final test before Melbourne?