Williams say Russian rookie Sergey Sirotkin has earned his place at the Formula One team on merit and is likely to surprise people this season. The 22-year-old will partner Canadian Lance Stroll, still only 19, at the former world champions after replacing retired Brazilian Felipe Massa. The Russian was previously a Renault reserve and finished third overall in the GP2 support series in 2015 and 2016.

A product of the SMP young driver programme established by Russian oligarch Boris Rotenberg, Sirotkin's rise has raised questions about how much it has been accelerated by his financial backing. "I think probably Sergey is one of those drivers you haven't heard of as much as maybe some other new talents who come into the sport, for whatever reason that may be," said deputy team principal Claire Williams at a team launch. "But I think he's going to surprise a lot of people this year. "His technical capability, combined with his track efficiency, is really impressive," added the daughter of team founder and principal Frank.

Both she and technical head Paddy Lowe rejected suggestions that money had influenced the decision. Sirotkin was chosen after a showdown between him and Poland's Robert Kubica, a former race winner seeking to return seven years after a near-fatal rally accident that almost severed his forearm.

"The selection process we used for that race seat was incredibly exhaustive, the most exhaustive I've ever been involved in, involving the technical team," said Lowe, who joined Williams last March from champions Mercedes. "Sergey was selected simply on merit for his driving," added the Briton. "That (technical) team knows nothing about the finances, they're not involved in it. They weren't aware of any factors like that. They made the call themselves on the data."

Lowe said he had no concerns about how well the Russian, only his country's third Formula One driver after now-departed Vitaly Petrov and Daniil Kvyat, would perform. He said Sirotkin, who first appeared on Formula One's radar when he joined Swiss-based Sauber in 2013 as a 17-year-old development driver, had served a "fantastic apprenticeship" in the junior series. "I think he couldn't be in better shape to hit the ground running as a new driver in Formula One," added the technical head.

Sirotkin, who has been spending five days a week at the Williams factory since the start of the year, told reporters he was ready to deliver when the season starts in Australia on March 25.