Highlights - Turkish Grand Prix
By Mark Hughes
BBC F1 commentary box producer
The contrast could hardly have been starker: in Istanbul Jenson Button looked majestic while his Brawn team-mate Rubens Barrichello appeared amateurish.
Button scored the most emphatic win of his career in Istanbul, while the veteran Brazilian almost stalled off the grid, fell practically to the back and then got involved in a series of incidents as he tried to make amends.
The tally for the two men this year now stands at six victories for Button, none for Barrichello.
But the difference between them is not as stark as it looks. Asked how he was going to break the cycle of Button's dominance, Barrichello replied: "It could happen in a second. Just one thing goes your way and suddenly it opens out in front of you."
Jenson is an incredible driver - I would say as fast and talented as Michael Schumacher but maybe not quite as consistent
His love of Silverstone - he scored a sensational victory there in 2003 and out-qualified Michael Schumacher three times in the six years they were team-mates, including twice starting from pole - makes him feel that the next grand prix would be a particularly appropriate place to get his season properly underway.
Speaking after the race in Turkey, Barrichello said: "I don't see Jenson just continuing like this all season.
"We've been very closely matched over the last three years and it makes no sense that suddenly I cannot drive to his level. I'm sure that I'm going to be winning races this year too."
It's something that Button himself acknowledges, saying: "I have got a very competitive team mate. He's my strongest rival. It's not as if I've got a newcomer or a guy that doesn't know how to win races. He's very competitive.
"When he was allowed to race Michael Schumacher as a team-mate he was very, very quick, quick enough to beat Michael sometimes.
"I've got used to winning this year and so when I don't win - which is going to happen, for sure, because it's just the law of averages - it's going to be a bit of a strange feeling."
Frustrated Barrichello explains retirement
Last season Barrichello out-qualified Button more often than vice-versa so it may seem puzzling that a completely different picture can emerge between the same team-mates in different seasons.
Button has stood accused of having lost interest when the 2007 and 2008 Hondas proved so uncompetitive. There may be an element of that, but it is also to do with how the cars have dovetailed with the respective driving styles of the pair.
Button tends to have a narrow 'band width' in terms of car behaviour - he needs it to have lots of rear-end stability, particularly under braking, to allow him to maximise his high momentum entry to a corner.
His beautifully silky style allows him to squeeze the absolute maximum braking and lateral grip from a progressive-handling and grippy car.
It's an advantage that is magnified in the wet. But should the handling become twitchy or inconsistent, such a style can be much less effective than Barrichello's more improvisational approach.
Button has suffered in the past from team technical personnel not realising the full significance of his specific demands of a car, specifically in 2001 when he did not compare well in the uncompetitive Benetton to team-mate Giancarlo Fisichella.
Barrichello loves Silverstone and took a brilliant win there in 2003
By contrast, one of Barrichello's strengths has been his more open-minded adaptation to specific car traits.
However, it is only now, in his fourth year as Button's team-mate, that Barrichello is seeing just how devastatingly fast Button is in a car good enough to be smack in the middle of that narrow band width.
"He is an incredible driver," said Barrichello earlier this year. "I would say as fast and talented as Michael, but maybe not quite as consistent. I think I am in a position to say this having been a team-mate of Michael's."
But much as Barrichello now realises all too well the level to which Button has lifted himself, he knows that there were days when he was able to be faster even than Schumacher. Not many, but enough to know that it must also be possible against Button at his peak.
Barrichello was notoriously Schumacher's Ferrari number two, in that often he was not allowed to compete with him. That is not the case with Brawn and Button. Nevertheless, it was still something Barrichello was eager to have reconfirmed before the Istanbul race.
After first discussing it with Button, Rubens requested that Jenson join him in seeking an audience with team boss Ross Brawn to get a reassurance that they were allowed to race each other. "That's true," confirmed Brawn, "and I told them that yes absolutely they could."
With that niggle out of his mind, Barrichello began to think how he might beat Button in Turkey.
He was fuelled slightly lighter and therefore at a strategic disadvantage and, worse still, had qualified one place behind. On the other hand, he was on the cleaner, grippier side of the grid and Button was not.
The start therefore was going to be critical, was probably going to define Barrichello's race.
The biting point of the clutch in an F1 car can be adjusted by the driver for how aggressive you feel you can be with your start.
A very sharp bite point means there is virtually no clutch slip and, if this can be combined with the optimum level of wheel spin, it is theoretically the fastest way of getting off the line.
Barrichello has sought reassurances from Brawn that he can race Button
But it's also the most sensitive. Get it just slightly wrong and, with so little clutch slip to fudge the issue, you are either going to light up the rear tyres with excessive wheel spin, or bog down disastrously.
If the car bogs down and the gearbox is over-torqued, the car's anti-stall device kicks in, taking control out of the driver's hands for a second or two until it ensures the engine does not stall. That's what happened to Barrichello in Turkey.
As he says, things can change in a second.
Mark Hughes has been an F1 journalist for 10 years and is an award-winning author of several books