Monday test pace genuine – Ross Brawn
Despite the Brackley based team sitting out most of the winter amid uncertainty about its future, the rebranded 'Brawn GP' car had heads turning at Barcelona as it went against every other rival car.
Button topped the morning session with the Mercedes-powered machine and was bettered only by the impressive BMW, Ferrari and Toyota by close of play at the Spanish venue.
But was the pace genuine or had the team drained the fuel tanks, possibly in a bid to entice sponsors?
"If everyone knew how much fuel we had on board, they would be surprised," Brawn told Auto Motor und Sport, who said the Briton was 'smiling' as he gave his answer.
"Even our engine partner Mercedes didn't believe it when we told them," he added.
Long before team owner Honda Motor Co. announced its departure from the sport, Brawn and his team colleagues were predicting a strong 2009 for what was intended to be the RA109 car.
"On the basis of our simulations, we knew what (test) lap times this car would do theoretically at Jerez, Bahrain and Barcelona. When we saw the times of the competition, we were surprised they were not quicker," Brawn revealed.
Most teams wrap up their 2009 pre-season programs this week, but Brawn GP will conduct a final three days of testing at Jerez next week.