New Ferrari signing Sebastian Vettel topped the timesheets in Jerez as pre-season testing ahead of the 2015 FIA Formula World Championship campaign but it was Mercedes who sent out the strongest message – with 2014 title runner-up Nico Rosberg putting in 157 trouble-free laps on day one, more than double the total of the next most consistent runners.

Meanwhile, McLaren, who were running their new Honda-powered MP4-30 for the first time managed just six laps with the package going through same teething troubles experienced by their rivals at the same time last year, when the sport’s new hybrid, turbocharged power units were first introduced.

Rosberg was quickest throughout the morning with the Mercedes driving logging almost a century of laps by the midway point of running. Top spot was wrested away from the German in the early afternoon, however, as Vettel went for a short run in the new Ferrari SF15-T. That netted the four-time world champion a time of 1:22.958 and top spot on the timesheet. He progressively bettered that benchmark and finished the day with a best time of 1:22.620, set on medium tyres.

Rosberg ended the day in third place with a best time of 1:23.106 but perhaps the relevance of the laptimes was underlined by new Sauber recuit Marcus Ericsson finishing in P2 with a time of 1:22.777, set on soft tyres.

“That was a great start to the winter testing,” said Robserg. “In the beginning it's all about reliability and we managed to do a lot of mileage today. The guys in the factories built a complete new car and now we come here and it's working great, so the team did a fantastic job over the winter. I was able to do some good long runs on the first day and that's really amazing.”

Encouragingly for Sauber, Ericsson did end the day with the second-largest total of laps, 73, a figure matched by Valtteri Bottas in Williams’ FW37.

Williams were slow to start running, with Bottas only completing his first installation lap some two hours after the start of proceedings. His first timed lap came an hour later. Once up and running, however, Bottas enjoyed a trouble-free afternoon and claimed the day’s fifth-fastest time.

Fourth place on the timesheet but at the top of the list in terms of making an opening-day impression were Red Bull Racing.

Lat season’s runners-up rolled out their RB11 car this morning with the new challenger sporting a striking, black and white “dazzle” livery of the sort used by motor manufacturers to disguise prototype cars.

With Daniel Ricciardo at the wheel, the team logged 35 laps on day one and despite calling a halt with a little over an hour remaining due to a technical issue, Head of Race Engineering Guillaume Rocquelin branded the outing a success.

“The day generally went according to plan, starting cautiously, building up the length of the runs and learning all the time,” he said. “We had a small issue with the brake controls system around lunchtime but you’re always going to have little niggles like that on day’s like this. We stopped running late in the afternoon with a technical issue, but it wasn’t too serious. An alarm went off on the engine and at that stage of the day, knowing that an investigation would take time we chose to stop. Aside from that, everything went pretty as we hoped.”

Ricciardo meanwhile admitted that he could feel an improvement from Renault’s upgraded power unit but he declined to say just how much.

“So the first impressions are good,” he said. “We’ll get a few more laps over the next few days but so far everything seems pretty encouraging. I can feel a step forward. I won’t go into too much detail but it’s there. We didn’t do a whole lot of laps but definitely more than last year! In general everything is behaving as it should. Obviously we had a couple of issues but once the car is running it’s all going pretty normally. A good first day, there are some positive signs there.”

Behind Bottas, Toro Rosso debutant Carlos Sainz was sixth fastest. The Spaniard racked up a decent total of 46 laps but brought out the red flags late in the afternoon with the day’s second stoppage. Ericsson had caused a brief halt in the morning with a spin.

That just left McLaren. The MP4-30 finally broke cover after two hours of the session had elapsed, with Fernando Alonso at the wheel.

The Spaniard put in three installations laps and then a short three-lap run that included just one timed lap.

Just seven drivers took to the track today. Force India last week pulled out of the trip to the Spanish circuit, while Lotus this morning announced a delay with their arrival at the track, the team’s E23 only landing in Spain at around 4pm this afternoon. The team later announced that with the car beginning this evening it does not expect to run before Tuesday morning.

2015 Testing Jerez – Day One
1 Sebastian Vettel Ferrari 1:22.620 60
2 Marcus Ericsson Sauber 1:22.777 73
3 Nico Rosberg Mercedes 1:23.106 157
4 Daniel Ricciardo Red Bull Racing 1:23.338 35
5 Valtteri Bottas Williams 1:23.906 73
6 Carlos Sainz Jr Toro Rosso 1:25.327 46
7 Fernando Alonso McLaren 1:40.738 6