Ex-Williams reserve driver Paul di Resta says the team’s 2018 driver line-up of Lance Stroll and Sergey Sirotkin is “a risky decision” given their combined lack of experience.

Di Resta was one of several drivers in contention to secure a seat on the Formula 1 grid with Williams this season. The Scotsman tested a 2014-spec car for the Grove outfit in Hungary last year alongside Robert Kubica, who was being assessed for a potential return to the cockpit.

Despite a successful test, di Resta missed out on the second seat and was replaced by Kubica as reserve driver, although the veteran of 59 grand prix’s felt he had a good chance of a full-time F1 drive.

Having seen his chances of a return to the sport fail to materialise, the 31-year-old believes the decision to partner Sirotkin with Stroll is a risk given the competition the team will face on-track.

“I was very happy with the test I did [alongside Kubica in Hungary],” di Resta told RACER.

“Exceptionally happy with the test I did. I had one of those days in a car that you couldn’t ask for any better, and I feel that I delivered to the best of my potential, which they can see.

“It’s a risky decision, the driver line-up, in the experience the guys have got. Obviously Lance has got a year under his belt, Sirotkin coming in… The key things for me is already you’ve got McLaren who are a key championship contender and Renault as a constructor should be able to beat somebody like Williams. Where does that fall within where you are in keeping the momentum?

“Obviously as the years go on, the experience of having a Mercedes engine diminishes a bit, so they’ve got a tough ask.

“But there’s more to the decisions than everything that comes out and fundamentally that board sat together and took what their best [decision] was from what they had on the table, for all the reasons that come into it.”