Claire Williams says Robert Kubica's commitment to Williams despite missing out on a 2018 race seat was pivotal in his selection in their line-up for next year. Kubica will return to the F1 grid after more than eight years away in 2019, having recovered from life-changing injuries suffered in a rally crash.
Kubica was overlooked in favour of Sergey Sirotkin for this season – a decision rumoured to have been as much about the Russian's financial backing as on-track performance.
Sirotkin has picked up a solitary point with one race of 2018 to run, while his backers SMP Racing claimed that they had taken the decision to remove their man from the team over the struggles of this season.
Esteban Ocon was another driver thought to be in the frame, but deputy team principal Williams explained the decision process to partner Kubica with George Russell next year.
"It's a great story, but to us it's not about the story, it's about choosing the best racing driver for us," she told Sky Sports.
"It's all part of the Williams puzzle to get us back to where we need to be.
"We did a full evaluation process with the pool of drivers we were looking at, but Robert has done a fantastic job for us this year.
"Even with the fact we didn't select him going into this year in the race seat role, he's still stepped up as our reserve driver and he's spent so much time with the team and he's been really impressive working behind the scenes.
"His commitment, his tenacity on what he wants and what he wants to see the team doing is really impressive, with the feedback he's been able to give and he's a good driving force.
"Just such a tenacity that he has after his injury is so super impressive and if he applies all that next year, I know he's going to do a great job for us."