Formula One's first pre-season test ended in Jerez today with Ferrari's Kimi Raikkonen fastest, Mercedes doing more laps than anyone else and McLaren once again bottom of the timesheets.
While Raikkonen completed 106 laps in the new Ferrari SF15-T car, and ensured Ferrari-engined cars set the pace every day, champions Mercedes showed off their reliability with the most distance covered.
Double world champion Lewis Hamilton did 117 laps, taking Mercedes' tally over the four days to 516 laps and equal to 2,284km, and was not worried about the times.
"It's been pretty amazing this week to see how reliable the car has been and how much mileage we've covered," said the Briton, who won 11 of the 19 races last year.
"We all loved the experience of last year and everyone wants to do it again. This is where you prove out the car -- looking for as many laps as you can, not searching for fast times.
"It's been really positive from that perspective and every day here the car has got better as we learn more about it," added the 30-year-old who was third on the day's timesheets.
McLaren, whose drivers managed only six laps each on the first two days at the wheel of the new Honda-powered car, managed at least to try some long runs even if technical problems again hampered them.
Jenson Button managed 35 laps, building on the 32 done by Fernando Alonso on Tuesday, but the day again ended early after what the team said was a fuel-related spark/ignition issue.
"Unfortunately, we've had a few issues this week - all of which have been pretty small - but cumulatively they meant we were stuck in the garage for quite some time," said engineering director Matt Morris.
"Still, our prime objective coming away from this test was to ascertain that the main car architecture worked, and we've done that."
Sweden's Marcus Ericsson was second fastest for Sauber, who failed to score a point in 2014 in their worst ever season. Seventeen-year-old rookie Max Verstappen was fourth in his Toro Rosso ahead of Brazilian Felipe Massa in a Williams.
The next test starts in Barcelona on Feb. 19 with the opening race in Australia on March 15.