Jenson Button believes the Red Bull Racing team has overtaken his Brawn squad in terms of performance, despite the Briton's victory in Bahrain.
Button scored his third win in four races in Bahrain, having started from fourth position after a difficult qualifying.
The Briton finished ahead of Chinese Grand Prix winner Sebastian Vettel, whose race was compromised after being stuck behind Lewis Hamilton in th early stages. The Red Bull racer finished seven seconds behind Button.
Despite his win, the championship leader reckons Red Bull has already leapt ahead of Brawn.
"This one was very sweet because we didn't expect it in a way as Saturday was very poor in qualifying," said Button. "Everyone has caught up and I think red Bull has actually overtaken us, so this one is great and all credit to the guys - it has been a tough few weeks for all of us away from home.
"The parts on the car are getting very old now, so we can go back to Europe, freshen the parts up, add the aero kit to the car and hopefully make another step forward."
Team boss Ross Brawn says the Brackley, UK-based squad will introduce updates from the start of the European season that should allow it to stay optimistic.
"We have a series for upgrades for Barcelona and beyond. We have to be optimistic. We have had no upgrades for the first four races, because there was nothing there."
He added: "Getting to the first race was as much as we could manage and there was nothing in the cupboard. The process is starting again from the point at which we were able to buy the company and we got our program well into the swing again and Barcelona will show us the benefit of getting it running again."
Brawn was also adamant that his team has all the necessary resources to fight for the title in the long run, but the Briton admitted he's not thinking of that yet.
"I believe so, but I am not thinking that wise," he said when asked if he thought his team has all the ingredients to win the title.
"We are going out there to win races. We have got a great driver pairing and we've had a painful restructuring of the company, that is behind us now, and everyone can see what can be achieved. I am optimistic. We have some great drivers the rest is up to us."