Williams "has to be concerned" about rivals' form - Stroll

Coming off the back of an unspectacular winter of testing, and with the likes of Renault, Haas and McLaren showing signs of potential improvement, Williams could face a tough battle to hang on to its fifth spot in the constructors' standings for a second consecutive year.

That's not lost on Stroll, who admits that Williams' testing form, paired with gains being made elsewhere on the grid, is cause for concern heading into the season opener.

"We definitely have to be concerned because it's not a secret that everyone looks pretty good this year, so it's going to be competitive," he said.

"But at the same time we just have to remain calm and wait to see what happens this weekend where we stand."

Team boss Claire Williams added that while testing hadn't gone to plan, it was the right time to uncover weaknesses with the car, leaving margin to make big gains when the major updates arrive for the Spanish GP.

"I suppose the honest assessment is we probably hoped for a little bit more in testing," she said.

"But then it is testing. That's what we're there for, to try to evaluate the way the car is and predominantly to understand where the weaknesses are and then work rapidly ahead of Australia in order to try to rectify those weaknesses.

"Any ambitions we may have had – I'm not saying we did – to be fighting in the top three are probably a little bit far off from us, but that's our responsibility and we need to make sure we very quickly get on top of the weaknesses in the racecar that we have and bring developments over the coming races.

"We've got a huge development package for Barcelona – we'll have to wait and see where that puts us."

However, she also conceded that losing points in the early races would likely prove costly in the tight midfield battle.

"I think that's what we all see – that you miss those points at the start of the season and you really regret that later.

"You kind of think 'well, it's a long year so if we don't do necessarily very well in the first few races it doesn't matter'. It actually is crucial to do well from the off."

According to new signing Sergey Sirotkin, one hope for the team is that issues with turn-in might have been exaggerated by the cold conditions in Barcelona.

"To be honest [turn-in is] the most crucial part of any racing car," he said.

"In certain conditions it was more difficult for us yes, and of course I'm sure you don't expect me to say what we need to sort out, but we are working on it.

"It's a very different track here anyway, with a different tyre working range.

"It all depends on the conditions, not just what the car is doing. Here we're going to be on a different surface and different air temps and different corner layouts. It's all going to affect the car balance quite a lot.

"We know areas we have to be improving, but we also need to be paying attention to the tracks."

Stroll echoed his teammate's sentiments about turn-in.

"For sure it's been something we've struggled with for a while now," he said. "Last year we had the same kind of problem at a few tracks. Some tracks less than others, but it's definitely a point to focus on to improve."

Additional reporting by Edd Straw and Scott Mitchell