Ross Brawn says Sebastian Vettel may have been guilty of being a "neutral passenger" as Ferrari's upgrades in 2018 backfired and suggested that a similar downturn would not have been allowed to continue over several races when Michael Schumacher was at the team.
An update package introduced for the Singapore GP went wrong as Ferrari suddenly lagged off the pace of Mercedes – having previously delivered an arguably better package across the European leg of the campaign.
The same package remained on the car in Russia and Japan – with Lewis Hamilton winning all three races to streak clear of Vettel in the drivers' championship.
Once the car was reverted to its previous spec, Kimi Raikkonen won the United States GP, and Brawn says Vettel could have spotted the mistake – and demanded it was rectified – earlier.
"Seb had a mixed 2018," Brawn told F1's official website. "He's had some very good performances, and played a big part in taking the team forward, but in the end, Seb and the team didn't deliver.
"They had a strong year but they have got to make that next step and deliver – and that's Seb and the team.
"I don't know the dynamic or chemistry in the team or Seb's relationship in the team or how that all works. He made one or two errors, which is unfortunate but with drivers, that can happen.
"The team seemed to make a wrong turn technically for several races and then they came back again to an older spec which corrected their form.
"As a driver you have to be involved with those things, you can't be a neutral passenger.
"I recall when I was at Ferrari, if we had something we were uncertain about, Michael would be banging my door down to talk about it and spend time with the engineers and work until he got himself comfortable with what was going on.
"That motivates a team and can be a catalyst for people to look at things in a different way or different perspective.
"The difference between success and failure is often down to small things. I don't think he or the team need to change things dramatically, they just need that final bit of polish to get off the line."