Germany's [ Images ] Sebastian Vettel [ Images ] ran away with the British Grand Prix [ Images ] in a Red Bull one-two while championship leader Jenson Button [ Images ] struggled home in sixth place on Sunday.
Britain's Button, winner of six of the first seven races, had his overall lead over Barrichello trimmed to 23 points after finishing off the podium for the first time this year.
The dominant victory, from pole position in a race low on incident, was Vettel's second of the season and third of his Formula One career.
The German, who also led Red Bull to a one-two in China in April, is now 25 points adrift of Button with nine races remaining.
"Thank you very much guys, this is a dream coming true. We've won the British Grand Prix," he said over the team radio after taking the chequered flag.
"This is what I was dreaming of when I saw the first grands prix at Silverstone in the era of (Britain's 1992 world champion Nigel) Mansell," he added later.
Italy's [ Images ] Jarno Trulli [ Images ] was seventh for Toyota [ Images ], with Ferrari's Kimi Raikkonen [ Images ] taking the last point in a race billed as a farewell to the track that hosted the first Formula One championship race in 1950.
Red Bull's superiority over the Mercedes-powered Brawn was underlined by Vettel lapping more than a second a lap faster than his rivals in the early stages, despite being heavier on fuel, and finishing 41.1 seconds ahead of Barrichello.
"I don't think we could have beaten them today," said Brawn owner Ross Brawn [ Images ].
Button, who had struggled all weekend for grip and to get heat into his tyres, started sixth but had fallen to ninth after the opening lap.
He worked himself back into the points and then made up two places at his second pitstop, when he switched to softer tyres and chased Rosberg all the way to the finish.
Donington Park is due to host the British Grand Prix next year, although Formula One supremo Bernie Ecclestone [ Images ] has said it will return to Silverstone if that circuit is not ready.