The Frenchman was clear from as soon as he tested new aero parts at the Spanish Grand Prix that it was not an improvement, and he subsequently made clear a few races later that he felt a focus on tyres was wrong.

Those messages helped Haas expose a wind tunnel correlation issue, which it was able to address in time to ensure the problems were eradicated from its 2020 design.

Reflecting on how important his technical feedback was last year, Grosjean reckoned that if he had kept quiet about his feelings then Haas could have been heading towards a particularly troublesome campaign.

In an exclusive interview with Motorsport.com, he said: "As soon as the Barcelona race, when we brought the evolution to the car, I immediately said that there was a problem and that it wasn't working.

"At Paul Ricard, after qualifying, I told them that we had to stop concentrating on the tyres because that wasn't the problem. There was another real problem with the car.

"That's when the studies were more thorough, and we realised that there was a real problem. It was a correlation problem between the wind tunnel and the track.

"What's certain is that if I hadn't said in Barcelona that the evolution wasn't working, they would have continued in the same direction and this year it wouldn't have gone well. That was definitely a positive point."

Grosjean has faith that Haas has learned from what went wrong last year, but reckons the opening minute of pre-season testing will be critical to confirming that. It's why too the team is not wasting any effort on an official launch, and will instead show its car in public for the first time in the pitlane on the first morning of the test.

"We're not making a presentation, we're just launching," said Grosjean. "We're going to concentrate on the essentials and really get the best out of the car as quickly as possible."

He added: "We're waiting to see how is the car on track. We have all the numbers from the wind tunnel. I think we've learned a lot from last year. Now, again, the only answer we're really going to get is when we run the car and see how it performs on the track.

"We've tried to understand where the problems of correlation come from. We've tried to understand what we have done differently from others, and we've looked at the concepts around us.

"And then we're going to wait for the first few laps in Barcelona to make sure that we measure everything that happens in the car and that we're in line with the wind tunnel."