Kimi Raikkonen put Ferrari back on top of the timsheets as Formula One’s first pre-season test of 2015 came to a close at the Circuito de Jerez in Spain.

The Finn’s best time of 1:20.841 came late in the day, on a soft tyre run, after he had spent most of the day heading the field on medium and hard tyres. His late flourish was also the fastest time of the test, a tenth of a second quicker than that set by team-mate Sebastian Vettel on day two of the four-day outing.

Yesterday, Sauber’s Felipe Nasr broke Ferrari’s grip on the top of the timesheets yesterday and today team-mate Marcus Ericsson kept the Swiss team at the top end of the order with a best time of 1:22.019, again set on soft tyres.

Lewis Hamilton set the day’s third fastest time with a lap of 1:22.172, 1.3s down on Raikkonen’s best. Perhaps more importantly his 117 laps took Mercedes test total to an enormous 516. The defending champion’s total for the day was set despite a morning spin that left his W06 stranded at the chicane.

An earlier stoppage was caused by Red Bull Racing Daniil Kvyat. Forty-five minutes into the session he stopped on track with the team later diagnosing an ERS problem that restricted the Russian to the garage for the rest of the morning.

He eventually returned to the fray just before 1pm and ran faultlessly thereafter, racking up 64 laps for the team’s biggest single-day total of the test.

“Once we’d sorted the issue the car ran perfectly all afternoon and we were able to get through the key elements of the programme we had mapped out,” said Head of race Engineering Guillaume Rocquelin. “This week has all been about establishing reliability and while we’ve had a few niggles the car is pretty much where we want it to be. We focused on medium and long runs all week and Dany was able to do more of that work this afternoon. We did lose track time over the four days and that’s always frustrating, as you inevitably have to scratch some things off the ‘to do’ list, but the major items were covered so I would say we’re leaving Jerez in pretty decent shape.”

Despite the positive spin, it’s been a tricky week for the Milton Keynes outfit, with their day two running being disrupted by a broken front wing and day three being compromised by the need to change a power unit.

McLaren also had a difficult final day. The team made early progress with the MP4-30, with Jenson Button posting 35 laps, but its running was cut short by a fuel pump issue. Button’s morning running had also been disrupted by an oil system problem.

“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 the team’s 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.

“Today, we had a couple of stoppages, but we were still able to get on with our aero progamme – obtaining correlation data for the guys back at the factory, just so we can check that everything’s working as we expected.”

Honda’s Yasuhisa Arai added: “Of course, we’d anticipated there would be issues – this is a test, after all – but the difficulties we faced here were more than we’d expected, so we weren’t able to get the running time we’d ideally wanted. Nonetheless, Fernando and Jenson’s feedback has been positive and comprehensive – they’ve given us some very good information.”

Elsewhere, Max Verstappen had a busy final outing of the week, putting 97 laps on Toro Rosso’s STR10.

“It was good to run STR10 in anger and after overcoming some niggling problems on the first two days, we managed to do some really high mileage on the final two,” said Toro Rosso Technical Director James Key. “That was useful, because it meant both our drivers managed to complete a full and comprehensive programme. Our focus has been entirely on reliability, while allowing the drivers to experience every aspect of the job. We haven’t done any work on performance so far and we will not do that until the end of the month, therefore we are not looking at our lap times for now. The important topics are reliability, consistency and driver work, to tune the car to their requirements and give them as much preparation time as possible.”

Romain Grosjean got a first taste of Lotus E23 but his running was cut short after 53 laps with a power unit problem.

Jerez Test – Day Four
1 Kimi Raikkonen Ferrari 1: 20.841s 106
2 Marcus Ericsson Sauber 1:22.019s 1.178s 112
3 Lewis Hamilton Mercedes 1:22.172s 1.331s 117
4 Max Verstappen Toro Rosso 1:22.553s 1.712s 97
5 Felipe Massa Williams 1:23.116s 2.275s 73
6 Romain Grosjean Lotus 1:23.802s 2.961s 53
7 Daniil Kvyat Red Bull 1:23.975s 3.134s 64
8 Jenson Button McLaren 1:27.660s 6.819s 35