Toto Wolff has admitted that Haas may be 'best of the rest' in Melbourne.
While it is clear that Mercedes, Red Bull and Ferrari will lead the way as the 2018 season begins, many think it will be the small Ferrari-linked Haas team in front of Renault and a densely-packed midfield.
"From our statistical data [Haas] seem very fast," Mercedes boss Wolff told Brazil's Globo.
"But if someone is 20kg lighter, the difference is eight tenths. I really hope they are there.
Former F1 driver and GPDA president Alex Wurz agrees that Haas may be the fourth force in 2018.
"Based on the tests, it is Haas," he told Der Standard.
"Otherwise it would be Renault, because they are a factory team on the uptrend. But basically the midfield is almost too close together for predictions."
Melbourne plays host to the first grand prix of 2018 this Sunday.