Some new analysis in the sport's specialist media claims the W03, to be raced by Michael Schumacher and Nico Rosberg this season, was actually quicker than all comers in the crucial 'long runs' during recent pre-season testing.
But Haug, Mercedes-Benz's motor sport vice-president, insisted it is unlikely the former Brawn, Honda and BAR team can leap from fourth in the constructors' world championship to first in just a single bound.
"You don't go from the the creation and restructuring of a team to (winning) the world championship in two years," he is quoted by SID news agency.
"The reigning world champions (Red Bull) didn't, and we didn't either (as engine supplier) with McLaren.
"You just have to accept this building-up period," added the German.