Williams Engineering has announced Sergey Sirotkin as its second driver for the 2018 Formula 1 season, partnering Lance Stroll.
Robert Kubica was the early favourite to get the seat vacated by Felipe Massa but dropped out of the running following Siroktin's impressive showing at the end-of-season Pirelli test in Abu Dhabi. Kubica will, meanwhile, return to Formula 1 as Williams’ reserve and development driver for the 2018 season.
Williams said throughout the process that its driver decision would be based purely on performance and it is believed Sirotkin was clearly the quickest at Yas Marina. It has been understood that the Russian has joined the team on a multi-year deal.
Sirotkin, 22, and Stroll, 19, will form 2018's most inexperienced F1 line-up.
"After an extensive driver evaluation process, I am thrilled to have our 2018 line-up finalised, and I'm excited to see what next season brings," said deputy team principal Claire Willliams. "We have taken our time to evaluate all the available options, and I'm confident Lance and Sergey can deliver the best results for the team."
"The Williams philosophy has always been to promote and develop young talent and Sergey fits right into that ethos," she went on to say. "Lance has had a record-breaking debut season, and with a year now under his belt, he will be ready to hit the ground running in 2018."
Sirotkin has spent the past two seasons with Renault as its test and reserve driver. He took part in six grand prix free practice sessions and two test days with Renault and subsequently tested Williams' car for the first time in Abu Dhabi.
"To say I'm happy and proud to join such a famous team like Williams is an understatement," said Sirotkin. "It took a huge amount of work to get where I am and I'm really happy and thankful to everyone involved."