From GMM

The 2009 championship has become effectively a race between teammates, after the Brawns finished one-two at Monza and their title rivals at Red Bull had a poor Italian grand prix.

"The man sat next to me here is obviously my big rival for the title now," said second placed Jenson Button, referring to his lead over winner Rubens Barrichello that shrank by 2 points to 14 on Sunday.

Red Bull's Mark Webber retired after a first lap clash, leaving his teammate Sebastian Vettel as the Brawns' closest championship rival after struggling to just eighth place.

The German's points gap to drivers' title leader Button, however, blew out to 26 points, meaning he needs to score an unlikely 7 points more than his British rival at each of the remaining four races to be champion.

Ross Brawn suggested F1 must now look within his Brackley based team to find the winner of the 2009 championship.

"All I ask from my drivers now is they compete fairly and openly, they have got to work together fairly, but they're old enough to deal with it," he smiled.

Sure enough, both Button and Barrichello said nothing will change now despite the fact the next four races will almost certainly see only one of them realise a lifelong dream of becoming world champion.

"There's that old saying that you can only win in formula one if you're tough. We're both nice guys, so this is the end of it," Barrichello told reporters in Italy.

"I think the best thing in life is respect. Obviously, when we're finding that the softer spring or the harder spring is the better thing for the car, you go to the other side of the garage and tell them that's what you have found.

"It's an open book there," said Barrichello. "We have our meetings and we both go through the check list at the same time, live, so we both can hear."

Meanwhile, Lewis Hamilton's defence of his 2008 world championship ended mathematically on Sunday.

With his crash while chasing second place on the last lap of the Italian grand prix, the McLaren driver also dropped out of striking distance of Jenson Button's title lead with four races to go.

With a perfect run of wins, meanwhile, 2007 championship winner Kimi Raikkonen could mathematically match Button's tally if the Briton scores no more points this season, but the Finn would still not be world champion.

In a points tie, the driver with the most wins is declared the champion, and Raikkonen would lose out against Button by a factor of 5 wins to 6.

The results of the Monza race means just three drivers are still in the fight with Button: his teammate Rubens Barrichello and the two Red Bull drivers.