Mercedes GP bosses Ross Brawn and Norbert Haug have warned that the team isn't quite at its best yet as it prepares for the season opener in Bahrain next weekend.
Although rivals Ferrari, McLaren and Red Bull have cited Mercedes and its drivers Michael Schumacher and Nico Rosberg as a major title threat, Brawn has played down expectations.
"We had a strong pre-season testing programme with the MGP W01 but we have not quite reached the level of preparation that we would have liked prior to Bahrain," he said.
"The car shows promise and we have a strong development programme planned for the season but there is a lot of hard work ahead to ensure that we will be in the fight for the title."
Haug agreed that it was likely to be a low-key start to 2010 for Mercedes.
"Judging our competitiveness for the first couple of races, my impression is that we are not quite where we want to be and I would not see our team in the role of favourites," he said.
"Having said that, I am fully convinced that the whole team and our drivers Nico and Michael are fully prepared to get on top of our job and fulfill our targets which are winning races and fighting for world championships."
But Brawn added that with the team having won the title in its Brawn GP guise last year, it had no intention of giving up its crown without a fight - especially as it was now representing the legendary Mercedes name.
"Everyone at Mercedes GP Petronas is proud to be representing the rich motorsport pedigree of Mercedes-Benz as we start the season as the first Mercedes works team for over half a century," he said.
"In addition, knowing that we go into the new season as the reigning World Champions gives the team confidence and a fierce pride to defend our position."
He also underlined that Schumacher and Rosberg were already working well together, despite fears of tension given the seven time champion's reputation for dominating his team-mates and Rosberg's ambitions to become a number one driver in his own right.
"I am very pleased with how our new drivers Michael and Nico have settled into the team and developed a close working relationship," Brawn said.
"They have really pushed the development of the car throughout testing and they will push each other to achieve better results on the race track."
Courtesy ITV Sport
