Valtteri Bottas set the fastest time on the final day of pre-season testing in Barcelona.
The Finn set a 1:23.063 on the super-soft tyres in the Williams but was still two tenths slower than Nico Rosberg's Friday benchmark of 1:22.792, the best time over the eight days running at the Circuit de Barcelona-Catalunya, which was also set on the slower soft compound Pirellis.
For Williams the final test has seen them really install themselves into the battle for best-of-the-rest behind Mercedes and such has been their confidence with the FW37 that the team ended their day with over an hour left to run having completed 86 laps in total.
Sebastian Vettel also used the red-marked tyres to claim second for Ferrari, four tenths of a second slower than the Williams, but the German also managed to avoid several red flags in the afternoon to complete a race simulation as the four-time world champion racked up 129 laps to conclude what has been a very successful pre-season for the SF15-T.
Mercedes marathon highlights key to 2015
As for the predicted pacesetters Mercedes they had a more low-key final day concentrating on longer runs as Nico Rosberg set the second highest lap tally of the day with 148 tours but only setting the seventh best time around 2.5 seconds slower than his best from Friday.
What is even more incredible about the Mercedes pre-season is team chief Toto Wolff revealed the team had used just one power unit over all 12 days of running with only occasional maintenance to keep it as fresh as possible.
That means that, that solitary V6 turbo hybrid has done over 6,000km. While there has been the odd blip with the electrical side of the Energy Recovery System that is still incredible reliability but it also highlights a key point about 2015 with only four power units allowed over the season, three of those will complete five races which totals over 1,500km plus use in practice sessions and qualifying sessions.
McLaren needing Red Bull recovery
It was another day of missed mileage at McLaren as Jenson Button managed just 30 laps on the final day.
After the hope created by reaching the 100-lap mark on Friday, the weekend carried on in the vein of the previous 10 with niggles in the Honda power unit keeping the MP4-30 stranded in the garage.
More sensor issues were the cause of their lack of running on Sunday, however, given if they need inspiration heading to Melbourne they only need to look at Red Bull to see who quickly things can turn around.
The RB10 was easily the worse performer of pre-season testing but come Australia, Daniel Ricciardo claimed second in a wet qualifying at Albert Park and would finish second in the race only to be later disqualified for surpassing the fuel flow limit.
While podiums are not likely for the Woking team this year, they can still be in the hunt for points given there does seem to be good raw pace when the car is running.
Red Bull remain dark horses
Speaking of Red Bull they had another mixed day as Ricciardo missed most of the morning with an ERS problem that caused the first red flag of the day.
In the afternoon, however, the Australian made something of a recovery managing 72 laps by the end of the day.
The pace of the RB11 is somewhat unknown, however, as even on the soft tyre runs the team were still running with plenty of fuel on board.
A best of 1:24.638 was well down on their expected rivals at Williams and Ferrari but as I mentioned they have never tended to reveal their true potential until Saturday afternoon in Melbourne.
Perez gets first taste of the VJM08
After Nico Hulkenberg completed over 200 laps in the first two days of running with the new Force India VJM08, it was Sergio Perez who got his first go behind the wheel on Sunday.
With the reliability of the Mercedes power unit clearly evident by the works team's achievement, the Mexican too was able to continue putting good mileage on the new car with 130 laps on the day.
Midfield battle shaping up
After the close battle with Sauber on Saturday, the gap between the two was much bigger on Sunday with Felipe Nasr putting a second between himself and Perez and that could translate to a difficult start to the season, usually Force India's strongest part of the year, with Lotus improving and Toro Rosso getting plenty of mileage too.
Despite their improvement since the switch to Mercedes engines however, Lotus were left to pack up early on Sunday as a brake problem saw Pastor Maldonado crash quite heavily at turn four and Toro Rosso too had their own problems as an engine problem meant Max Verstappen missed a large proportion of the afternoon.
Next stop: Melbourne
But after 12 days of testing that is it, the next time we shall see the cars turn a wheel will be Friday morning in Australia as the 2015 season is now less than two weeks away.
Mercedes head Down Under the clear favourites but the battle behind is fierce. The other big story will be whether Manor Marussia, their official name on the 2015 entry list, will also make it to Albert Park as work continues to make the most incredible comeback since Brawn GP made a similar return from near-death in early 2009.
I'll be doing a full season preview here on GiveMeSport as well as looking at other stories heading into the first race and the latest news too. Hold on to your hats race fans F1 2015 is almost here!