McLaren team boss Martin Whitmarsh says it is wrong to regard Brawn GP as an underdog operation, and believes it will take some time for the pack to catch Ross Brawn's squad.
Whitmarsh reckons Brawn is reaping the benefit of its predecessor Honda having thrown resources at the 2009 rules rather than developing its 2008 car - a choice McLaren did not have as it was embroiled in a title battle.
"I suspect our good friends at Brawn GP aren't going to be stand still and wait for us, so they are going to be moving as well," he said.
"The reality is they have a much more developed car, it is very clear, and they openly admit they have been developing the car for 16 months with huge resource in Honda to develop the car they have today.
"It was a good strategy for where they were. We were doing other things like winning world championships, so I think now is the time when we have to push and we've got to make quicker progress than they are, but we are not going to catch them in the next few races, that is for sure."
He said the investment Honda had made prior to selling the team was key to Brawn's dominant performance.
"I think currently they have 700 people on their books so numerically they are probably the largest chassis team in F1," said Whitmarsh.
"I know they are sadly reducing at the moment and having had some insight to their finances, I don't think they are underfinanced either.
"The car they have today was a product of 16 months development, initially in four wind tunnels and then in two wind tunnels, so I acknowledge that in the future they might be a small team, but what we see today is the consequence of a huge, huge effort from the Honda team.
"There is no magic in F1, there is big effort and they have done a good job."
Brawn, along with Toyota and Williams, is at the centre of the row over diffuser legality. McLaren was not among the teams that protested, but Whitmarsh agreed that the three squads were gaining from their interpretation of the rules.
"We haven't participated in any protest this weekend, we will concentrate on making our own cars go quicker," he said.
"Undeniably, if you accept this more adventurous interpretation of the regulations, then there is a significant performance benefit. That is very obvious, it has been obvious on the timesheets all weekend."