Mercedes finished the final pre-season test in Bahrain as clear favourites for this year's championship, with Lewis Hamilton clocking the fastest time on the last day on Sunday.
The Mercedes driver may have failed to record the ultimate fastest time of the two tests in the Gulf kingdom by a mere two-hundredths but his car has emerged as one of the most reliable machines coupled with the capacity to post consistent quick laps.
"This has definitely been the most challenging winter I've experienced and the car is still very much a work in progress," said Hamilton, who was delayed in the morning by a gearbox issue. "There’s so much to learn with these new cars; it's just mind-blowing."
Mercedes-powered teams have the biggest advantage heading into the season-opener in Australia in two weeks' time as Williams displayed in the four days.
"I think with this amount of testing we are as prepared for Melbourne as we can be," reckoned Valtteri Bottas.
McLaren, struggling to refine setup and eke out the performance, stumbled on the final day completing just 22 laps. Jenson Button was sidelined for most of the day after a high-mileage internal combustion engine failure forced the team to replace it, taking a considerable amount of time and was later afflicted by an undiagnosed control electronics problem.
New regulations introduced this season have handed all teams with several headaches, suggesting that no manufacturer was immune to the emerging gremlins.
Nevertheless, even perennial mid-fielder Force India showed the relatively strong reliability of the Mercedes power units clocking over 400 laps in its four days, coupled with ending two on the top of the charts.
Moreover, 11 of the 12 fastest times set over the course of the three tests came from Mercedes-powered cars.
FERRARI: THERE AND THEREABOUTS
|© AP Photo/Hasan Jamali
Fernando Alonso was third in his Ferrari but had a troubled outing as he was halted by the need to change the gearbox on the car before the lunch break, losing track time for the second straight day.
"The team did its utmost to carry out changes on the car as quickly as possible, but again today, we had planned to do more laps than we managed," Alonso said. "There are a lot of things to learn with the use of the power unit to improve the performance of the car and we are not yet where we want to be."
Sauber is the other team that's powered by the engines from Maranello, and the Swiss team managed to round a massive 177 laps; the most mileage by any team on a single day in this year's pre-season tests.
Having missed the entire Saturday due to an engine issue, Adrian Sutil covered up the lost time in the morning before handing over to teammate Esteban Gutierrez in the afternoon.
"Now we have a lot more data to analyse," Sutil said.
RENAULT, RED BULL IN THE DUMPS
|© AP Photo/Hasan Jamali
Despite continued niggles, Red Bull managed 77 laps while sister team Toro Rosso managed a little bit more.
"We tried to do a race distance today; for one reason or another that didn't work out," Vettel said. "Obviously it's difficult to know where the car is. It's not just the number of laps you do, but also the type... We know we have to catch up in a lot of areas."
Red Bull has a filming day scheduled for Monday, where it will try and complete 100 kilometres.
And for the fourth straight day, Lotus ended its session by clocking just 30-odd laps. A power unit problem halted its testing yet again and heads for the season "with a lot of unknowns."
"We’re not in an ideal situation," confessed Romain Grosjean.
Caterham has been the most reliable of the Renault runners, highlighted by the maximum mileage it accrued in the three tests, including on the final day.