Swapping Esteban Gutierrez for Kevin Magnussen during the off-season has brought out the best in Romain Grosjean; according to Guenther Steiner.
Last season Grosjean was Haas’ only points-scorer as Gutierrez struggled to get up to speed.
The Mexican racer was dropped after one season, replaced by former McLaren driver Magnussen.
This has seen a more even competition with Grosjean leading the qualifying stats seven to four and scoring 18 points to his team-mate’s 11.
Asked how Magnussen’s arrival at Haas had impacted on Grosjean, team boss Steiner told Autosport: “He reacted very well. I think he took it down as a challenge.