Lewis Hamilton and Fernando Alonso shared the same positive feeling after Friday practice ahead of this weekend's Spanish GP.

The world champion as the fastest man in the afternoon at the Circuit de Barcelona-Catalunya, however, it was actually his teammate Valtteri Bottas who posted the best time overall in the morning.

A combination of blustery conditions making mistakes common and tyres not particularly suited to the technical layout made for no real pecking order despite Mercedes' pace.

And the threat posed by Ferrari and particularly Red Bull was not lost on the four-time world champion.

"I think it is going to be relatively close between the top three teams but I can't really say who is quickest at the moment," he commented.

"It was so windy out there, every driver was struggling with the changing direction of the wind.

"You're constantly arriving at each corner and the wind direction is never the same, so we saw lots of drivers going off.

"These conditions make it very difficult to define where the set-up needs to go," he added. "I'm hoping that it's cooler and calmer tomorrow."

Despite the uncertainty, Hamilton was still positive about the general performance.

"The day was pretty good. We got through all our running and were quite fast compared to previous years [but] we've got some work to do overnight," the 33-year-old concluded.

Bottas largely echoed his Mercedes partner but would highlight the likely need to improve the performance on the softest compound in use.

"I didn't really feel any gain of grip with the SuperSoft compared to the other tyres," he confirmed. "We will have to work on this area for tomorrow."

Red Bull's pace on the red-striped tyre over a long run was particularly noticeable, as they ran faster for longer than the Brackley-based rivals.

However, commenting on his team's chances, Max Verstappen believes the engine deficit could still be crucial.

“It’s hard to overtake here so we need to be competitive in qualifying. We know that in qualifying they will turn up their engines," the Dutchman claimed.

“Turn 3 is easy flat and Turn 9 is also flat so that becomes a straight and then we will lose even more in terms of engine speed.

“It’s a bit of a shame but we can improve our car for the final sector and we need to play to our strengths.

“In general it’s been a positive day and the updates are working. But we always want more.”

Still hopeful of one day joining the top three battle, McLaren has brought one of the most noticeable upgrade packages including a brand new front nose design.

Pace over a single lap still seems to be lacking, however, with Stoffel Vandoorne ninth and local favourite Alonso only 12th.

The double world champion was sure that his MCL33 had made progress in terms of performance, however.

“The upgrades we brought here are a step forward,” the 36-year-old said. “There is more performance in the car – it felt better and there was more grip.

“It has been a positive Friday and we’ve tested everything we brought here.

“There’s still some debate about some of the parts, but we seem to be a little bit more competitive here than any of the other Fridays this season."