Jenson Button thinks McLaren must begin outpacing Red Bull Racing on track - rather than hoping it does a better job on race weekends - if it is start making the gains it needs to win the world championship.
With McLaren confirming on Thursday that both Button and Lewis Hamilton will run with the blown diffusers in Friday practice - after the team ruled out initial plans for back-to-back tests - hopes are high that the developments can give the team the performance the lift it needs to take the fight to Red Bull.
And Button is not only confident McLaren has improved its blown diffuser enough to race it in Germany for the first time, but he also thinks it vital the team ups it form.
"If we can get this blown diffuser to work we should be competitive and quick enough to really challenge the Red Bulls for victory here - and we have to," said Button at Hockenheim on Thursday.
"It is the 11th race of the year. Red Bull have obviously won more races than us, and if they are consistent they will be very difficult to beat this season.
"This update has to be a step forward for us around here so we can challenge for the victory. We have to be challenging for victories at every race we go to now. We cannot just be hoping that we do a better job on the race weekend."
Button reckoned that improvements made by McLaren to the blown diffuser had overcome the heat problems that affected its performance in Silverstone.
"Our heat issues, we have pretty much sorted them out - so that is good," he said. "It is just finding the performance in the floor that we didn't completely find at Silverstone. I don't think this really hurts us too much."
Hamilton was equally upbeat about the progress on the blown diffuser, but admitted that there was still plenty of work to do.
"I think we are confident that we have made another step forward in understanding it, and we will try to improve it and try to make it work better than it was then," he said.
"But we still plan on running lots of sensors and that kind of thing to understand it fully. I'm sure it's still not optimised, so we'll keep on working with it, and I'm sure the other teams have to do the same thing. So we don't expect this weekend for it to be bang on perfect."