Williams chief technical officer Pat Symonds says Valtteri Bottas is approaching his peak in terms of driver performance and is expecting the Finn to continue his upward trend in 2017.
Despite Williams' frustration in 2016 having slipped to fifth in the F1 world constructors' championship, Symonds says both Bottas and Felipe Massa were shining lights this season and a pleasure to work with.
QUIZ: Which F1 team should you drive for?
With Massa retiring from F1 at the end of the year, Williams sees Bottas as its lead driver for 2017 having signed FIA European Formula 3 champion Lance Stroll for his rookie campaign.
After the shock retirement of F1 world champion Nico Rosberg, Bottas was instantly added to the shortlist of potential replacements and in recent days has become a front-runner which led to Williams reportedly rejecting requests from Mercedes about the Finn.
Speaking before Rosberg's retirement, Symonds says after a rocky debut year in F1 when Williams' car performance let down Bottas, he has seen a remarkable rise in the driver's performance which he believes can continue to spike in 2017.
“I think the learning process is continuing well,” Symonds said. In my mind 2013 wasn't his first year in F1, it was a dreadful year and I think we had to do a reset and start him off again in 2014.
“So, his third year he has now got to a good level and can be confident for next year with him performing strongly at every race. He has done a good job this year, I am very pleased with him.”
Nico Rosberg retires! And 10 other 'I wasn't expecting that' F1 moments
Bottas joined the Williams ranks back in 2010 as a test driver while in Euro F3 before going on to win the GP3 Series title in 2011.
After a year out of racing as Williams third and reserve driver, Bottas made his F1 race debut in 2013 and has gone on to notch up nine rostrum results in 78 F1 Grand Prixs.
Latest Tweets from Crash.net & GPF1rst