Sauber tweet:, external "Short-runs underway. This time with soft tyres."

Felipe Nasr has gone further than anyone else today, with 55 laps on the board as I type. A soft-tyre run of 1:24.852 has just put the handsome C34 into second place.

Image source, Sauber

1. Valtteri Bottas (Williams) 1:23.063

2. Felipe Nasr (Sauber) 1:24.852

3. Nico Rosberg (Mercedes) 1:25.186

"Although Force India was only running the 2014 car at the last test it had five transporters in the paddock, three of which expand into double-deckers. Both the 2014 and 2015 cars will be in those transporters and heading back to the team's Silverstone base later tonight."

Image source, knutson

A 1:23.063 for Bottas on the super-soft tyres. That's the third best time of the Barcelona tests, beaten only by Nico Rosberg's 1:22.792 on Friday and Lewis Hamilton's 1:23.022 yesterday.

Ominously, those Mercedes times were achieved on the slower soft compound tyre.

Bottas now has super-soft boots on.

Stand by yer beds.

The Williams of Valtteri Bottas is humming along beautifully this morning.

The FW37 was already the quickest car out there today but the Finnish driver has just pulled further clear. Now on the soft tyre he has a best lap of 1:23.859, more than a second clear of anyone else.

Force India tweet:, external "New best for Checo - 1:26.414 to go into P4. #FeelTheForce"

Andrew Benson
Chief F1 writer

"Even more important than whether the McLaren car works, the big question surrounding the team is whether Fernando Alonso will be fit to race in Melbourne after suffering concussion in his accident a week ago.

"There are still unanswered questions about what caused the crash, but McLaren racing director Eric Boullier sounds pretty confident about his star driver being available. He said the driver line-up would be firmed up 'as soon as the green light is given by the doctors, which should be next week'.

"Kevin Magnussen, who would replace Alonso if the Spaniard cannot drive for medical reasons, also sounded like he did not expect to get the call. 'It should be possible to step in,' the Dane said. 'But that's not my worry at the moment. It looks like he's fine. That's the good news and hopefully everything will be as normal.'"

The Williams of Valtteri Bottas goes to the top of the list with a 1:25.009 set on the Pirelli development tyre.

Pirelli confirmed this morning that the development tyre is equivalent to the regular medium rubber.

1. Valtteri Bottas (Williams) 1:25.099

2. Nico Rosberg (Mercedes) 1:25.186

3. Max Verstappen (Toro Rosso) 1:26.267

Image source, Getty Images

Felipe Nasr (Sauber) - 36

Nico Rosberg (Mercedes) - 34

Sebastian Vettel (Ferrari) - 30

Max Verstappen (Toro Rosso) - 27

Pastor Maldonado (Lotus) - 26

Sergio Perez (Force India) - 23

Valtteri Bottas (Williams) - 22

Daniel Ricciardo (Red Bull Racing) - 10

Jenson Button (McLaren) - 0

Red Bull tweet:, external "After a good start on the final day of testing, the #RB11 has had an ERS problem. The Team are looking into it."

The RB11 had done 10 laps before the gremlins struck. Its best time was a 1:26.587.

Andrew Benson
Chief F1 writer

"Only Force India have done fewer miles than struggling McLaren, which is hardly surprising given their new car only ran for the first time at lunchtime on Friday.

"Given its youth, Nico Hulkenberg has piled on a lot of laps. 'Impressions are good,' he said on Saturday. 'Straight out of the box in one afternoon, almost 80 laps; two and half race distances today. That's very good and positive and we were able to do some good and proper work. It is a little bit similar to last year's car, so straightaway we found a good basis to work from. We have achieved a lot and everybody is as happy as they can be.'"

The Toro Rosso of Max Verstappen has elbowed its way up to the sharp end, a time of 1:26.267 on the soft tyres good for second pace.

"The reason why the red flag period didn't last very long is because the Red Bull mechanics were able to push the car back from where it had stopped at pit exit - so no time was wasted loading it on the tow truck."

Image source, knutson

"Williams' Chief Technical Officer Pat Symonds says that the FW37 is running in full Melbourne-spec. There will be a couple of new parts added to the car when it arrives at the Albert Park track, but this is the version of the car that will race in the Australian Grand Prix."

Valtteri Bottas is currently second for Williams with a best time of 1:26.440 from 19 laps spent mostly on the medium tyre.

Ferrari tweet:, external "Last day in Barcelona."

Image source, Ferrari

Don't know what everyone else thinks but in my humble opinion Sebastian Vettel's simple helmet design is the nicest he's ever had. And he's had a few...

That was an easy enough one to tidy away and we're off again.

Andrew Benson
Chief F1 writer

"Red Bull have been keeping well under the radar so far this winter, apparently not doing a single run on low fuel, and only rarely even using the soft tyre. Despite that, up and down the pit lane engineers believe they are in the heart of the mix behind Mercedes and Daniel Ricciardo agrees.

"'It's clear Mercedes are strong,' he said. 'For the rest it's still a bit of question mark. But I think we're in that next group with Williams and Ferrari. We've got to pull in those silver cars but if we can do that we're looking good.'

"He did allow that Red Bull appeared to be looking 'more competitive' on high fuel. But then they have not really done any shorter runs on low fuel as yet. If history is anything to go by, that may well remain the case on Sunday as well."

Daniel Ricciardo's Red Bull RB11 is stranded at the pit exit and we have our first red flag of the day.

Andrew Benson
Chief F1 writer

"This is far from the first time I have said this over the winter, but the news is not good from the McLaren pit. They had hoped to spend the final day of testing proving out reliability and perhaps doing a race simulation if there was time.

"But after an hour of the session there is still no sign of Jenson Button and the team say they have a 'bit of a delay with today's programme'. They blame systems checks - which begs the question why these were not completed before the session started - and say they 'hope to be out later this morning'."