Brawn focused on the perfect execution of a KERS-slaying strategy to make their Valencia victory secure - and four crucial laps won Barrichello the race.
McLaren had shown they were the team to beat in Hungary and it was no surprise to see them on the pace again in Valencia. Nor, with warmer conditions, was it a shock to see Brawn back at the front. The biggest surprise was Red Bull's lack of speed that put them out of the equation before the race even began.
Mark Webber revealed their problem was a surprising aerodynamic inefficiency. To generate the required downforce levels for Valencia, Red Bull had to increase the amount of wing on their car (less efficient than gaining it from efficient underbody aerodynamics) more than their rivals did.
That meant they gained more drag than their rivals and suffered reduced top speed on the straights, culminating in an overall increased lap-time.
Brawn already knew from practice that their sole focus should be on McLaren and how to get over their KERS advantage (which was more its gain in overall power rather than its overtaking opportunities) and they made a conscious decision to run their cars relatively heavy in Q3 and accept conceding pole to McLaren - because that was the best way to beat them overall in the race.
Sure enough, Lewis Hamilton and Heikki Kovalainen qualified 1-2 and when the car weights came out Brawn's hand was shown.
"If you're just in front of them but on the same fuel load, they pass you at the start and then you are in trouble," Brawn explained after the race.
The way to beat them would be to qualify just behind on a heavier load, run longer and overhaul them in the pits - a strategy Button messed up due to a loose qualifying lap and a bad opening lap, but one that Barrichello executed perfectly.
Hamilton knew the only way to overcome Brawn's strategy was to fly at the start, and he duly set the fastest lap in 14 of the 15 laps before stopping with just under nine seconds advantage over third-placed Barrichello.
It did not work so well for second-placed Kovalainen, however, who was much slower (although McLaren denied backing him into Barrichello, declaring his pace was the best he could do) and he pitted with just 1.2s advantage over Barrichello.
Calculations suggested that every extra lap out on the track would give the car yet to pit around one second advantage, so with four clear laps Barrichello would easily pass Kovalainen. But instead of taking it easy, knowing the first stint job on Kovalainen was done, he focused on the gap to Hamilton and put in four fast laps followed by Hamilton-beating in and out laps.
It was this that effectively won him the race.
Between Hamilton's in-lap on lap 16 and Barrichello's out-lap on lap 21, the Brawn driver gained 5.62 seconds relative to his McLaren rival and came out 3.3s off the lead.
In the second stint, Hamilton ran super soft tyres and Barrichello was on softs (which would be expected to be slower) yet the Brazilian maintained the gap and when Hamilton went in for his second stop he still only had a 3.686s advantage. Barrichello then had four clear laps in the bag to close that down - an easy task considering Hamilton would be coming out full of fuel and on the harder tyres.
That's why McLaren tried to take a gamble and keep Hamilton out one more lap. Doing so would have given Barrichello only three laps with that advantage and there may have been a slim possibility for Hamilton to stay ahead.
But they made the call too late, and once Hamilton was in and the extra lap could not be run, Barrichello's earlier pace meant that there was no way he could be held off.