Red Bull improve on second day
Red Bull enjoyed their most productive day of pre-season testing so far offering hope they are finally starting to get over their troubles.
The previous nine days had seen the world champions fix a litany of problems, many to do with overheating, leaving them languishing in a lowly ninth of the 11 teams on the overall lap chart.
But on the second day of the final four-day test in Bahrain, Daniel Ricciardo clocked up 66 laps, with his best a one minute 35.743secs.
It is the first time the RB10 has dipped under 96 seconds over the six days so far at the Sakhir circuit, finishing just 0.173secs off the pace set for the second successive day by Force India's Sergio Perez.
Following his final run in the car ahead of first practice for his home grand prix in Australia in a fortnight, Ricciardo said: "A big improvement everywhere over yesterday and a much more optimistic outlook now I think.
"We still have a lot to learn and understand, but we're making progress and the past two days have been a big step in the right direction."
Rivals Force India, Ferrari and Williams again focused on long runs and reliability, which is something that still eludes Red Bull, chalking up 108, 122 and 103 laps respectively.
Ferrari's Fernando Alonso sandwiched Perez and Ricciardo on the timesheet, whilst Williams' Massa finished a second off the pace.
Jenson Button was fifth quickest, but only completed 52 laps - the second lowest total behind the 31 of Lotus' Pastor Maldonado - after suffering a gearbox issue on track that required a considerable period of time to fix.
Button said: "We got back out at the end and everything ran smoothly, which was good.
"It was a shame to lose that time. It's the first major issue we've had this winter, but it's better to suffer it here rather than at a race weekend.
"The basic car is good, and there's a great deal of potential there, but there's still a lot of work to do."
Button brought out one of four red flags, as did Lewis Hamilton via a minor excursion into a gravel trap in his Mercedes early on.
Hamilton was then comfortably out in front on the lap chart when his car encountered a gearbox problem that brought his day to a premature end.
With Mercedes starting to encounter the odd gremlin here and there, Hamilton said: "We've still got some work to do in terms of both reliability and speed.
"There are no specific problem areas, just lots of different things we need to improve.
"It's important to get as much mileage under our belts as we can and just as important to discover any problems before we get to Melbourne.
"It might be frustrating at times, but finding them at this stage is actually a positive."
Hamilton had to settle for a lap of 1:39.041secs for seventh fastest, finishing behind Jules Bianchi as Marussia also had a constructive day.
Bianchi completed 75 laps, with the Frenchman's best being a second ahead of Hamilton who managed 89 overall.
Like Red Bull, sister team Toro Rosso were able to put some laps on the board as Jean-Eric Vergne managed 61, finishing four seconds off of Perez.
For Sauber, who have looked strong so far, Esteban Gutierrez managed 106 laps as it was again a case of reliability over speed as he was 4.4secs down on his fellow Mexican.
For the two tailenders, Maldonado and Caterham's Marcus Ericcson, their day ended with minor fires on board their cars that brought out the other two red flags.