Haas F1 team knows Romain Grosjean outperforming its maiden car

The Frenchman gave Haas a dream F1 debut with sixth in Australia and followed that up with fifth at the next race in Bahrain.

The last three grands prix have been tougher, with Grosjean struggling with the balance, but he still managed eighth in Russia.

When asked by Autosport if he has been impressed with how quickly Grosjean has delivered for Haas, the American said: "The true test of a driver is a driver who can take a 15th-placed car and take it to 10th because the car does not have the ability to do that.

"That is what we are looking for in our drivers, to take a car that is not so good and get superior results.

"If you can do that, that is what a winning driver is.

"I think when you look at our drivers that is what sets Romain apart."

Haas praised the way Grosjean has matured in recent years, following a period at Renault where he lost his way and made several mistakes.

"His experience of making all those mistakes, he does not do that anymore," he said.

"He understands what he has got to do and when he obtains a piece of real estate in front of another car, he does not give it up.

"It is so easy to lose a couple of positions just like that and it is almost impossible to get them back.

"What I appreciate is his ability once he gets a position, he maintains it and puts everything he has into it to stay at that position.

"He is very opportunistic, when a little bit of grey cloud opens up he goes right through the middle and charges forward.

"That takes a lot of experience and that is why some of the more seasoned drivers seem to be able to do that.

"They make it look easy but it really is not."