Valtteri Bottas has signed a new one year deal to race for Mercedes in the 2018 Formula One season. The Finn has impressed alongside Lewis Hamilton at the team that has won the last three drivers’ and constructors’ championships. He has won twice this year and although expected to maintain his drive, the team had held off confirming the deal while the 2017 driver market remained fluid.

The one-year deal allows Mercedes to keep their options open, with Daniel Ricciardo contracted at Red Bull until the end of 2018 and Max Verstappen contracted with the same team until the end of 2019.

The 28-year-old joined Mercedes at short notice at the start of this year, after the current world champion, Nico Rosberg, shocked the team by announcing his retirement after taking the title in 2016.

Bottas, who had raced in F1 for four years for Williams, had little time to acclimatise to running with a top team but has proved capable of stepping up and most importantly has struck up a new, successful partnership with his team-mate. He has won twice this year, in Russia and Austria, scored two pole positions in Bahrain and Austria and nine podium places. He has 197 points from 13 races and is third in the drivers’ championship.

“As a driver, I’ve been able to learn and grow massively, and we have already enjoyed some really good moments this season that I will never forget,” he said. “I’ve been very impressed by the mentality, commitment and the team spirit this team holds. Partnering Lewis has also been really good, and I’m enjoying the respect we have and the will to push this team forward together.”

Hamilton, whose relationship with Rosberg became increasingly fraught by the end of last season, has enjoyed a much improved dynamic with Bottas. At the Hungarian Grand Prix Bottas allowed Hamilton past as the British driver attempted to catch the leaders but, when that bid failed, Hamilton gave back the place to the Finn.

Mercedes have allowed the two drivers to race this season and Bottas has proved to be a strong team player, which will have been a major part in their decision to retain him. Crucially in a championship fight in which Hamilton leads Ferrari’s Sebastian Vettel by three points with seven races remaining, Bottas has proved more adept at denying Ferrari points than Vettel’s team-mate Kimi Raikkonen has been against Mercedes.

His contribution to the title run-in, in which he is likely to be expected to support Hamilton’s attempt to take a fourth championship, may prove vital for the British driver.

“We gave Valtteri a big challenge this year: joining the team at the eleventh hour, stepping up to the forefront of F1 and pairing with the sport’s best driver as his team-mate,” said the Mercedes executive director, Toto Wolff. “With that in mind, his results have been probably even more impressive.

“For our team, the bonus factors are the respect and sportsmanship that have grown between our two drivers. The chemistry and dynamic between Valtteri and Lewis work and are what we need to take the fight to our competitors.”