More woe for Red Bull in Bahrain

Day One of Formula One's second pre-season test in Bahrain saw Mercedes-powered teams to the fore as Red Bull again struggled.

Besides Lewis Hamilton's Mercedes W05, the cars of Force India and McLaren also featured prominently in both reliability and pace - the latter increasingly set to become a factor as teams continue to follow the learning curve set by 2014's technological shift.

Nico Hulkenberg led the way with a 1:36.880s that saw the Force India end the session a full second clear of the field - the lap albeit set on soft tyres.

A notable omission among the Mercedes-powered cars was the Williams FW36 of Felipe Massa, which completed just five laps in all. Yet the total racked up by Nico Hulkenberg, Hamilton particularly and McLaren's Kevin Magnussen - the latter pair third and fourth fastest - once again put the rest in the shade.

Sebastian Vettel could have been forgiven for seeking the nearest palm tree in order to cool off as Red Bull again found themselves in the mire, with the World Champions not taking to the 5.412km Bahrain International Circuit until 1.45pm local time.

Red Bull and Renault have both worked flat out to try and get a handle on the overheating problems they suffered at Jerez three weeks ago and although Vettel set the fifth fastest time of the day, his tally of just 14 laps will hardly inspire renewed confidence.

Furthermore, the RB10 also stopped on track once again - its driver stood forlornly by the car with just over an hour of running remaining. There were four red flags in all during a session, the start of which was delayed owing to a shortage of track marshals.

Perhaps they were all too busy ogling Lotus's new E22, which finally broke cover after missing the first test. The car's 'twin tusk' nose has already attracted plenty of comment and the team have also opted to try something different at the rear, with a wing mounting that appears to bend around the exhaust.

Despite being first out on track, Romain Grosjean managed a total of just eight laps as software and battery problems intervened, with the car ending up ninth fastest overall. Ahead of him, Caterham once more led the Renault-powered teams in terms of laps covered - 67 for Robin Frijns - and although Toro Rosso also edged out Lotus, Daniil Kvyat managed a paltry five laps in total, with the STR9 also stopping on track.

While both Red Bull-backed teams pulled down the shutters in their garages first thing, Ferrari were among the early risers - although Fernando Alonso was soon back in the pits with smoke pouring from the back of his F14 T.

A 'fuel mix' problem was diagnosed and Alonso was soon back on track, maintaining the Scuderia's assured start to 2014 with the second fastest time set in his 64 laps.

Adrian Sutil managed 81 laps in the Ferrari-powered Sauber to wind up sixth fastest - the German albeit spinning his C33 as happened more than once in Spain - with Marussia's MR03 managing just three laps in the hands of Jules Bianchi.

In effect, Thursday's running represents the halfway point for teams on the steep, winding road to Melbourne and it could be argued that, having covered 383 laps to Red Bull's 35, Mercedes are 10 times farther along it.

Furthermore, with Hulkenberg's lap quicker than the fastest set in last year's race, signs are emerging that Mercedes' PU106A has power as well as durability. Renault Sport President Jean-Michel Jalinier met with Red Bull team boss Christian Horner and advisor Helmut Marko in the paddock on Wednesday; oh to be a fly on the wall.