Haas team principal Guenther Steiner believes Mick Schumacher has improved as an F1 driver but conceded his season has been "up and down" as the German's future hangs in the balance.
Schumacher is believed to be in direct competition with compatriot Nico Hulkenberg for a seat alongside Kevin Magnussen next season.
A difficult qualifying in Brazil looked like it would have hit his chances had a decision not been made by the time, though a resurgent sprint proved just what Schumacher could do.
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An inauspicious start to the campaign looked set to leave Schumacher lagging in the team with Magnussen scoring upon his return to the sport and whilst results compared to the Dane improved through the year, expensive crashes gave Steiner and owner Gene Haas food for thought.
Assessing Schumacher's season ahead of the final race of the year, Steiner said: "I mean, his job is a little bit up and down.
"The whole season, I mean, we all know he had very good moments and very bad moments, you know, it's an up and down."
Insisting progress had been made by the 23-year-old across the course of the campaign, Steiner added: "I think he got more consistent.
"He obviously improved, you know, because the beginning of the season was very tough, when he was thrown in at the deep end, with a better car, with a very good team-mate.
"It was a little bit of ‘OK, this is now Formula 1 for real’, you know, but then he recovered and got better."
Schumacher reveals "prove them wrong" attitude
Ahead of what could be his final F1 race for the foreseeable future, Schumacher is adamant the hardest moments are part of the path to success.
On his biggest takeaway from the season, Schumacher said: "Don’t stop believing in yourself and prove them wrong.
"Formula 1 is my life, I love every single moment of it and the learnings and tough times, that’s all a part of it and it’s just a matter of how you go about it and cope with it.
"That’s when you know if you’re made out for this sport or not.”