Kimi Raikkonen ensured Ferrari ended the opening pre-season test of 2015 as the quickest team, with the fastest time on the final day at Jerez.
The Finn posted a 1:20.841 in the afternoon to pip his team-mate Sebastian Vettel's best from Monday by just a tenth of a second.
Sauber's Marcus Ericsson also ensured four consecutive days of Ferrari-powered one-two results at the top of the timings with another soft tyre run in the afternoon, seeing him edge Lewis Hamilton's Mercedes by just over a tenth, though both men were over a second slower than the Prancing Horse.
Max Verstappen also continued to gain more F1 experience as he was fourth for Toro Rosso with Felipe Massa a quiet fifth for Williams. Lotus had to curtail their day early after an issue with their power unit and were sixth as Daniil Kvyat and Jenson Button brought up the standings for Red Bull and McLaren respectively.
McLaren making progress
Despite ending the test with the slowest time overall, lap time was never the aim of McLaren-Honda in the first test since their re-collaboration. Instead it was finding the flaws, ironing out the glitches and ensuring the new power unit could run smoothly, and on those grounds they have certainly made progress.
A total of 75 laps over the four days may not sound like much but given that McLaren haven't taken the safe approach with Honda, going for immediate performance rather than reliability, their best time of 1:27.660 may look slow but it's certainly comparable to where Ferrari were at the same point last year, and ahead of Renault.
Remember too, Honda only have a single team's data to go on which is a positive because all the attention is in one place and the engine only has to be compatible with one car design, although it does reduce the amount of data the Japanese carmaker can gather.
The data they have accumulated, however, will be plenty for the engineers to go back to base with and improve and refine. Then the focus can be on completing longer runs at the second and third tests in Barcelona later this month.
Red Bull in trouble
Perhaps the word trouble is a little strong but certainly Red Bull are not where they wanted to be after four days of testing. Renault have admitted a small metal shaft in the power unit was found to be faulty just a week before Jerez, leaving no time for the part to be improved. Yet with a full engine change on Tuesday, followed by ERS issues on Wednesday it seems the problems go a little deeper than that.
Certainly the issues are made to look worse compared to the progress sister team, and fellow Renault users, Toro Rosso made completing around 350 laps over the four days compared to Red Bull's 165.
Some of that will likely be down to extremity of the RB11's design and also Toro Rosso will likely be happier running in a more safe engine mode to give their rookie drivers time. However, they will certainly hope the issues Red Bull did have mechanically - Kvyat's front wing issue on day two excluded - are solved and that more meaningful running will be done in Barcelona.
Ferrari back on track
The biggest surprise of the test was certainly Ferrari; they were reliable and fast and have definitely got Mercedes looking over their shoulder. While its too early to declare them as genuine contenders this season, Sebastian Vettel and Kimi Raikkonen both have reason for optimism after dismissing this year as simply developmental.
Naturally Mercedes will turn up the power a little and continue to improve as testing goes on and a far better barometer will come in Barcelona, where more direct comparisons to 2014 can be made. But given the change in management, and the work of designer James Allison, it seems the Prancing Horse will certainly be galloping a little more in 2015.
Mercedes still team to beat
What is still undisputedly clear after the first test of the year is that Mercedes remain the team and the power unit to beat in 2015. As Nico Rosberg and Lewis Hamilton surpassed 500 laps for the four days, the reliability of the Silver Arrow is what is the most impressive.
It was not bulletproof but then these power units - such are their complexity - will likely never reach the stage of the old V8's which almost never failed, but the fact they were able to go so far so early in pre-season is what leaves the bigger impression after Jerez.
Yes, the Mercedes was never the quickest car on track, but then they never set the timing screens alight last year before reeling off 16 wins in 19 races.
Of course this is purely speculative, but given the ease with which Rosberg completed 308 laps over his two days, whereas Hamilton had a little more trouble on his, it could be that the German has settled in to the W06 quicker than the world champion. That of course will have no bearing on how the year plays out.
There will be more analysis from the first test as well as reaction and other news from the world of F1 in the coming days, with the fate of the German Grand Prix and the potential return of Marussia making headlines so keep eyes peeled here on GiveMeSport.