Haas team principal Gunther Steiner says he does not agree with the criticism levelled at Kevin Magnussen regarding his work ethic.
Magnussen left Renault at the end of 2016 after a single F1 season, with managing director Cyril Abiteboul telling French media Magnussen lacked discipline and commitment.
Sources at Renault and former team McLaren, with whom Magnussen raced in 2014, have also questioned his work ethic - but the Dane has argued his old teams have never given him negative feedback in those areas.
And Steiner says he has seen nothing in the first half of the season to suggest that criticism of Magnussen, who joined Haas on a multi-year deal, is justified.
“I don’t know where that comes from because that is not what I experience,” he told Motorsport.com.
“Kevin now has got a trainer with him, a very good guy which helps him in all aspects of life.
“I haven’t known the Kevin from three years ago, therefore I could not say, but I have never seen that he’s lacking effort or anything.
“He is different, as a personality he’s more of an introvert but I don’t want to change people’s personalities. That’s his personality. He does his job. Is he the guy that is outgoing? No. But that’s fine.
“As long as he does his work and he’s very positive to the team and his feedback is good.”
No "blame culture"
Magnussen has scored 11 points so far this season - more than his tally for the whole of last season - which currently leaves him seven adrift of teammate Romain Grosjean.
The Dane says he feels comfortable at Haas and is enjoying working in a team where there is “not a blame culture”.
“I feel very much at home,” he said. “I feel great in terms of the support I get from everyone in the team. It’s a really good environment to be in for a driver.
“[In other teams I’ve been in], I’ve experienced a lot of competition in the team between engineers, management etc.
“Here it seems there’s much better harmony between everyone in the team. Nobody is really competing against each other, everyone is working with each other for the same thing.
“It’s always good to be in an environment where everyone sticks together and it’s not a blame culture.
“Whenever we have a problem, we don’t spend time blaming each other - we spend a lot of time finding the solution.
“We trust each other, there is a big element of trust in the team.”