Ross Brawn admits his Mercedes team are struggling for pace with the start of the new Formula One season fast approaching.
It begins in Melbourne on March 27th, with just five more days of testing in Spain next week to come beforehand.
Brawn says they're about a second off where they want to be, which is at the front, so they've got to find a second in the upgrade.
However he says you never know what others will do - they've set out their plan and they'll know at Melbourne if it's right.
Brawn admits that having enjoyed success in his days with Benetton, Ferrari and Brawn GP, life under the Mercedes banner was proving more challenging.
His drivers - seven-time world champion Michael Schumacher and Nico Rosberg - failed to muster a win between them in 2010.
