Ross Brawn has admitted Mercedes GP is currently too weak technically to take on F1's traditional grandee teams.
The German squad, formerly run as Brawn GP following Honda's exit at the end of 2008, had hoped to compete for wins in 2010 as Michael Schumacher entered the second year of his F1 comeback.
But team boss Brawn told German Sky: "The reason we are not as successful as we would like is that the team is not physically strong enough."
Both Schumacher and Nico Rosberg have new race engineers in 2010, while former Renault technical director and team boss Bob Bell has joined the Brackley based team.
These things go step by step, season by season
He said he is seeing "progress" but insisted: "These things go step by step, season by season. For next year's car we will have a much stronger team than now."
Reports earlier this year revealed that the current car, the W02, has the shortest wheelbase in the entire field.
"When we made the decision on the layout, we had information that led us to believe it was right. In retrospect, we would probably decide differently," said Brawn.