Mercedes ‘not going forwards’ says gutted Rosberg
Although quicker than his famous teammate Michael Schumacher, the young German had been hopeful that a big package of upgrades for the W01 car – including a Red Bull-style exhaust layout – would pull Mercedes to the front.
"This is just as bad as Montreal," Rosberg told German television Sky.
"It's a huge disappointment, because it was said that our season is just beginning here. Our aero package did not function in the way it should have.
"We are not going backwards, but we're not going forwards. That's the problem."
There were rumors prior to Valencia that this upgrade package was a final roll of the dice before team boss Ross Brawn switches the team's entire focus to 2011.
"We are pushing very hard to develop the car and sometimes in pushing so hard, you trip over," he said on Saturday. "We need to reflect, assess and see what our next steps should be."