Russian driver Sergey Sirotkin believes his Williams Formula 1 test opportunity in Abu Dhabi could turn out to be the most important in his career.
Sirotkin, a three-time GP2 race winner, has taken part in seven grand prix practice sessions and a number of in-season tests during his time as test driver with first Sauber and then Renault.
Backed by SMP Racing, he has been on the Renault's books since early 2016, but will join the Grove-based Williams team for the post-Abu Dhabi GP Pirelli test.
Williams still has a free seat going for the 2018 F1 season, and will have Robert Kubica – who is favourite to land the drive – alongside Sirotkin and team regular Lance Stroll.
Asked by Motorsport.com whether this would be the most important test day for him, Sirotkin said: "In the year? Yeah, I'd say so."
Pushed on whether it'd be the biggest test of his career, he added: "We'll see how it goes – then we'll know. Maybe it will be."
Sirotkin is slated to drive the Williams FW40 on Wednesday morning, and expects to be running for three quarters of the day before handing the car over to Kubica.
"First and foremost, this is a tyre test. There won't be so much time during the two days, so I must make the most of it.
"I think everyone understands very well that we're not doing this just because I want to relax in Abu Dhabi on Monday, drive around on Wednesday and go home – but instead with an understood, firm, clearly defined goal in mind.
"I am certain this is how the team is approaching it as well. So... I won't say more, but I think that already it's possible to take some conclusions.
"Firstly, I have to do well in the test, and then talk about whatever else."
Asked whether he feels he'll have enough running, Sirotkin said: "It's around three quarters of the whole day, so it's a fair bit of mileage and a sizeable number of tyre sets – of different compounds – with both short runs and long runs planned.
"But the programme, as you know, isn't set by the team but by the tyre supplier, because it's their test – so it'll be what it'll be.
"Is that sufficient or not? Hard to tell. I think that, if something is not enough, everybody would understand. So this doesn't change my task – I'll do the most of what I can do."
The Russian acknowledged there would a comparison made between the drivers piloting the FW40 in the Abu Dhabi test, but advised against looking at fastest laptimes.
"I know that when the track is at its best, at certain points on day one and day two, I won't be the one driving.
"In the final hours, when it's quite cool after the sun sets, the track will cool down and the air will be fresher. And there's a lot of laptime in that. So I wouldn't pay too much attention to the specific numbers.
"But I think there's always a comparison every time, everywhere and in everything. So, whatever the conditions are, I have to do the best that I can.
"And I know that if I do what I'm capable of, it'll be enough – so that's all simple."