Gene Haas admits his years of struggling in NASCAR was the reason he aligned his F1 team so closely, and controversially, with Ferrari ahead of 2016.

The Haas team has enjoyed a remarkable start to life in Formula One, with Romain Grosjean finishing sixth in Australia and fifth in Bahrain. Haas is powered by Ferrari and has as many parts from the Italian team as allowed under the regulations, while it also enjoyed extensive use of the Maranello wind tunnel last year.

That arrangement was controversial and last year the FIA closed the windtunnel loophole for future new entries. Haas' entry model to F1 has concerned some on the grid, with Williams technical chief Pat Symonds suggesting it could "erode" the status of being a constructor team.

Grosjean has said Haas is still 0.5s off reaching its true potential, suggesting further positives behind such a tie-up. Team owner Haas says he saw no point entering F1 in the traditional sense when there are so many things for a new outfit to learn in the sport.

"The learning lesson in NASCAR is you need to pick your friends wisely," Haas told ESPN. "There's no use going there learning things the hard way. We learned that here. We chose to be very, very careful how we put everything together in Formula One. It sort of works."

Haas joined NASCAR in 2002 before its first full season the following year but struggled to establish itself as a competitive force on the grid until Tony Stewart took over half the team in 2009. The partnership allowed Haas to call on Stewart's ability as a driver and to attract better staff and sponsors, with drivers' titles following in 2011 and 2014 for Stewart and Kevin Harvick respectively.

Haas F1 team boss Guenther Steiner brushed off the criticism of its Ferrari partnership after Grosjean's fifth-place finish in Bahrain, saying the regulations allow anyone to take the same route into the sport.

"I'm not concerned about the criticism," Steiner said. "People will always critique. I would rather that we are critiqued for doing good than felt sorry for for doing badly. The regulations are the same for everybody, so everyone else can do it. We didn't get an advantage from it, it's only other teams didn't do it, so why would we get critiqued?"

Gene Haas interview conducted by Bob Pockrass