Jenson Button continued his dream start to the 2009 season in Monaco by leading Brawn's second straight one-two sweep, beating his team-mate Rubens Barrichello again.
Ferrari enjoyed its best race of the year so far to take third and fourth with Kimi Raikkonen and Felipe Massa, but Mark Webber's fifth place was little consolation for Brawn's usual main rival Red Bull, which saw Sebastian Vettel crash out early on.
Flawless starts from Button and Barrichello established the Brawn duo in first and second places by the opening corner, with Raikkonen fending off Vettel to hold on to third.
Both the Brawns and Vettel had started on the delicate super soft tyres, and it was the Red Bull that started to struggle first - soon lapping as much as three seconds off the pace.
That allowed Massa, Nico Rosberg and Heikki Kovalainen to close right in, with Massa crawling all over the Red Bull until he cut the chicane in avoidance when caught out by its early braking. The Ferrari then lost out to the opportunistic Rosberg as well as he let Vettel back past.
Rosberg got past Vettel on lap 10, with Massa and Kovalainen swiftly following, prompting the German to pit and fall into the midfield. He then slid into the Sainte Devote barriers while pushing to caught up soon after.
The Brawns began to lose pace around the same time, but Button coped much better with the situation than his team-mate. Nose to tail early on, the gap between the Brawns became 15s by the time the first stops were complete.
Button managed to make his tyres last until lap 17, and with Barrichello and Vettel having held up the rest of the pack between them, he had no trouble retaining his lead.
With both the Ferraris on relatively short first stints, they were unable to jump Barrichello despite his tyre issues, and from then on Brawn was set for a commanding one-two. Barrichello able to match Button's speed once both were on the harder tyres, but by then the gap was too great.
The Ferraris lurked close behind until falling away when it was their turn to use super softs in the final stints. They still did enough to resist the chasing Webber, who had to nurse his own tyres.
Rosberg and Fernando Alonso (Renault) lost touch with this group by running very long middle stints. The plan was to minimise the time on super soft tyres, but their slow times on heavy fuel mid-race cost them too much ground and they finished sixth and seventh.
Kovalainen would have been between them had he not spun into the Swimming Pool barriers at two-thirds distance. With his team-mate Lewis Hamilton making little progress from the back of the grid and finishing 12th, it was a depressing race for McLaren at what the team hoped would be its best weekend of 2009 so far.
Toro Rosso's Sebastien Bourdais at last had something to smile about after narrowly beating fellow one-stopper Giancarlo Fisichella to the final point, although ninth was still hugely encouraging for Force India. Kazuki Nakajima was set to complete the top ten in the second Williams until he slid into the Mirabeau barrier with one lap to go.
Toyota and BMW's poor weekends continued with 10th, 11th and 13th places for Timo Glock, Nick Heidfeld and Jarno Trulli, and retirement for Robert Kubica.
Nelson Piquet and Sebastien Buemi were the first to drop out of the race - the Renault driver extremely frustrated after the Toro Rosso ploughed into the back of him at Sainte Devote on lap 12, taking both into the barriers.
PROVISIONAL RACE RESULTS The Monaco Grand Prix Monte Carlo, Monaco, Monaco; 78 laps; 260.520km; Weather: Sunny. Classified: Pos Driver Team Time 1. Button Brawn GP-Mercedes (B) 1h40:44.282 2. Barrichello Brawn GP-Mercedes (B) + 7.666 3. Raikkonen Ferrari (B) + 13.443 4. Massa Ferrari (B) + 15.110 5. Webber Red Bull-Renault (B) + 15.730 6. Rosberg Williams-Toyota (B) + 33.586 7. Alonso Renault (B) + 37.839 8. Bourdais Toro Rosso-Ferrari (B) + 1:03.142 9. Fisichella Force India-Mercedes (B) + 1:05.040 10. Glock Toyota (B) + 1 lap 11. Heidfeld BMW Sauber (B) + 1 lap 12. Hamilton McLaren-Mercedes (B) + 1 lap 13. Trulli Toyota (B) + 1 lap 14. Sutil Force India-Mercedes (B) + 1 lap 15. Nakajima Williams-Toyota (B) + 2 laps Fastest lap: Massa, 1:15.154 Not classified/retirements: Driver Team On lap Kovalainen McLaren-Mercedes (B) 52 Kubica BMW Sauber (B) 31 Vettel Red Bull-Renault (B) 16 Piquet Renault (B) 11 Buemi Toro Rosso-Ferrari (B) 11 World Championship standings, round 6: Drivers: Constructors: 1. Button 51 1. Brawn GP-Mercedes 86 2. Barrichello 35 2. Red Bull-Renault 42.5 3. Vettel 23 3. Toyota 26.5 4. Webber 19.5 4. Ferrari 17 5. Trulli 14.5 5. McLaren-Mercedes 13 6. Glock 12 6. Renault 11 7. Alonso 11 7. Williams-Toyota 7.5 8. Raikkonen 9 8. BMW Sauber 6 9. Hamilton 9 9. Toro Rosso-Ferrari 5 10. Massa 8 11. Rosberg 7.5 12. Heidfeld 6 13. Kovalainen 4 14. Buemi 3 15. Bourdais 2 All timing unofficial