Sauber team boss Frederic Vasseur believes that in Marcus Ericsson and Charles Leclerc, the Alfa Romeo Sauber team has a "strong driver duo".
Last weekend Sauber confirmed their driver line-up for the 2018 season as they unveiled their new Alfa Romeo livery.
Pascal Wehrlein has lost his seat despite scoring all five of Sauber's 2017 points while Ericsson was retained following his point-less season.
The Swede will partner 2017 Formula 2 champ, Leclerc.
"We are all delighted about the cooperation with Alfa Romeo," said Vasseur.
"We created the foundation for our partnership at the Alfa Romeo Museum in Arese, Italy.
"With Marcus and Charles, we have a strong driver duo for the debut season of the Alfa Romeo Sauber F1 Team.
"Marcus is an experienced Formula One driver, who knows the procedures and the team well, after having worked together for the past 3 years. He is a team player and has a very positive attitude.
"Charles has proven his talent in several racing series, most recently winning the Formula 2 World Championship title.
"He had the chance to drive in four FP1 sessions and two tyre tests for us this season and convinced the team with his professionalism and charisma.
"I look forward to going into 2018 with this driver pairing, and I am convinced that they will complement each other very well."
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