Williams starts to show its hand

Fans of the Williams Formula 1 team may well be getting excited as we come towards the end of pre-season testing, and perhaps with good reason.

The first two tests of 2015 have been solid, but deliberately unspectacular for the Grove-based F1 squad. It has quietly gone about its business, focusing on the basics of the FW37's set-up, trying to improve areas of operational weakness last year (such as pitstops), and putting plenty of mileage on a Mercedes engine that must do more races this year before it can be changed without incurring penalty.

Meanwhile, the world champion works Mercedes squad has caught the eye with ominous long-run pace and frighteningly fast laptimes on the medium-compound Pirelli tyres. At last week's Barcelona test, new Mercedes customer Lotus set the ultimate pace, thanks to Romain Grosjean's last-day flier on supersoft rubber, but Nico Rosberg was less than 0.3s slower in the W06 - on mediums.

Williams will be hoping to have closed up on Mercedes over the winter © XPB

Such similar pace between cars on tyres two full steps different in compound is remarkable, and although he tried to play it down afterwards, Rosberg's lap was also fractionally faster than anything Red Bull, Ferrari or Williams managed on the soft tyre last week...

But all the teams will claim the second test meant little, and that this final one is the test that counts - the one where they need to get their collective acts together in readiness for the first race in Melbourne.

Today, for the first time, we got a glimpse of what Williams might be able to do this year. Felipe Massa set the fastest lap of the Circuit de Catalunya so far in pre-season testing. The Brazilian's 1m23.500s best lap on soft tyres - an effort he described as a "good lap" - was over three seconds faster than Williams managed to qualify on here last year (on one of its weaker circuits).

Perhaps more encouraging than the headline laptime is that Massa managed to lap within roughly three tenths of Rosberg's eye-catching effort from the last test when the FW37 was shod with medium tyres.

It's difficult to extrapolate, of course, given the laps were completed on different days, in different conditions, with (possibly) different fuel loads. But it's as close as we have got thus far to a like-for-like comparison, and it seems (especially given that Massa reckoned he lost 0.15s passing a slower car in Turn 3) that Williams is certainly right in the mix.

Massa reported after his penultimate day in the car that an upgraded single-pillar rear wing, turning vanes and other detail aero changes to the FW37 were working well.

"It was giving what we expected and that is good," Massa says. "We didn't have any problems, any instability that you can have in the rear wing. It's a delicate point to work so it was good."

Rear instability was a big problem for last year's Williams, which ate its rear tyres too hungrily over a race distance. The team tried several times to introduce a better rear wing, but couldn't get it to work properly within the limitations of free-practice running at grands prix.

If Williams has now conquered this problem, while retaining the straightline speed advantages it enjoyed from its low-drag philosophy last year, it could be in great shape.

"We are still quickest on the straight; we are working to just make the car a little bit better in terms of downforce, but we still have an efficient car in this area," confirms Massa.

Rear tyre management was a Williams weakness last season © LAT

"And [today] I think you see that, when we wanted the laptime, it was good, on a track where we were not in great shape [last year].

"I think it can be positive. I don't know actually to answer 100 per cent if we really made a step, but compared to last year the car is easy to drive and is a little bit better, a bit more stable.

"We still need to work on degradation, because it is not low, for many people, maybe not Mercedes! But for many people it is not low. So we work to make the car more consistent, but it was a positive day."

CHANDHOK'S VIEW

Massa clearly isn't getting carried away with himself, which has been a pre-season theme for Williams, but his performance on-track today certainly impressed ex-F1 driver Karun Chandhok, who was watching trackside for AUTOSPORT.

"This morning I watched the second half of the lap and the Williams looked really good," Chandhok says. "It looked very easy to drive, it was on a long run and Massa appeared to be driving really within himself - he wasn't using the kerbs, he had no lock-ups and he wasn't looking wild.

"The times were still really competitive - he was within eight tenths or so of Lewis Hamilton [on medium tyres] and I was surprised because I thought he would have been much slower.

"This afternoon I went to the first three corners, and then to Turn 4; he did around five laps on the medium tyre after the red flag and the car looked like it had a lot of understeer, but it was quite consistent and the pace was reasonable so I think it was Williams doing race work.

"They were putting understeer in to try to protect their rear tyres as that was their weakness last year.

"Then he pitted and did one or two laps on the medium tyre with much less understeer. I thought, 'OK he is getting ready for a qualifying run here', and sure enough he came out on softs.

"He only did one lap when he did his fastest time and the lap looked good, but it still looked controlled. Both of his two fastest laps looked quick but controlled, so I think they have got a bit more in the tank.

"I was genuinely really impressed with Williams today."

Like Massa, Chandhok reckons Mercedes, which only completed half a day's running before being sidelined by an engine problem, still holds a crucial edge. But he believes Williams could run Mercedes closer than last year at certain tracks, and maybe (stay calm, Williams fans), just maybe, win the odd race this season.

"I would put Williams second behind Mercedes from what I've seen so far," Chandhok adds. "The Merc looks mega, it looks perfect, Lewis can do whatever he wants with it. His only problem is getting temperature in the tyres, but obviously when you go to a hotter race it will be fine.

"What could be interesting is a race like Melbourne, where you don't get scorching temperatures and the surface isn't very abrasive, so it is not that easy to generate tyre temperature. That may be a problem for Mercedes; we will have to see.

Raikkonen looks more at home in the Ferrari this year, reckons Chandhok © LAT

"The thing you always have in the back of your head is, will Mercedes allow Williams to win? It doesn't look good for your customer team to beat you.

"But I think Mercedes likes to see a battle, as long as it is all-Mercedes cars, and I get the feeling they wouldn't mind Williams winning a few races."

THE REST

While arguing Williams looks a potential bit-part challenger to Mercedes this year, Chandhok also reckons Ferrari has closed up dramatically after a terrible 2014.

"I thought the Ferrari at slow speeds looked really good, and Kimi Raikkonen looked as good as Daniil Kvyat's Red Bull did through the slow corners," he says.

"Kimi looks much happier this year - it is a car he can drive - but in the high-speed corners I don't think they are as good as the Williams.

"I think the Ferrari is infinitely better than last year, but I would still say: Mercedes, then Williams, then Ferrari versus Red Bull, depending on the circuit.

"The Lotus was a strange one. Romain Grosjean looked messy today, like he was overdriving and trying to force a laptime out of it. Obviously the engine is going to help them and it looks a much better car than last year's, especially through high-speed corners.

"The Toro Rosso, I really wonder if they are running different engine maps to Red Bull. The back of the car always looks like it is moving around too much on traction. It just looked a bit wild.

"It looks like Carlos Sainz turns the wheel very aggressively too, but I'll reserve judgement until tomorrow [when Verstappen is in the car] to see if it's a driver thing.

"The Sauber, honestly it just looked like a heavy racecar, with a lot of fuel on board when I was watching, although they did go for some low-fuel runs later.

"McLaren? Well, McLaren is McLaren..."