Highlights - European Grand Prix
After a fourth consecutive poor result for Jenson Button at the European Grand Prix, the world championship leader is clearly feeling the pressure.
When the title is at stake you often see drivers raise their performance to a higher plane. Mika Hakkinen and Damon Hill did it when they closed in on their championships, and last year Felipe Massa raised his game even though he ended up just losing out on the title.
Button, who eventually finished seventh despite being the fastest man on the track for much of the second half of the race, holds an 18-point lead in the championship. He has been really lucky because his main rivals - Red Bull drivers Mark Webber and Sebastian Vettel along with Brawn team-mate Rubens Barrichello - have not consistently seized the opportunities Button has offered them.
Button is now tightening up in the car. His first lap in Valencia was rather clumsy
The drives he put in earlier in the season were some of the finest I have commentated on. They were champion's performances without doubt. His easy command of the Monaco circuit was a pleasure to witness and he was utterly peerless in Turkey.
Up to now he has massively impressed me with his calmness, the way he has attacked qualifying, and the great overtaking moves we have seen in early laps.
But now Button is tightening up in the car.
His first lap in Valencia was rather clumsy, and he overreacted to an inevitable chop off the line from Vettel. Clearly off balance he then ran across the 'no man's land' at Turn Four, meaning he had to yield to Webber before he finally settled down in an initial ninth place from fifth on the grid.
Can he lose the championship from here? Of course he can.
Button himself was saying before the weekend: "I've lost 15 points in the last three races to Webber and I can't lose five points a race or I'm in trouble."
He got lucky in Valencia as Webber was off the pace and he was able to get ahead of the Australian during the pits stops with some fine pace on his in and out laps.
There are still 60 points remaining, and he is 18 ahead of second-placed Barrichello, but Button has to stop finishing in the tail end of the points. That is a double whammy because it would be wholly unreasonable to now expect Barrichello to support his championship crusade.
Button 'happy' for Barrichello
I don't believe Rubens can outscore Jenson by 18 points on pace alone in the same car, but reliability and incidents can soon change that.
In the past, we've seen these championship fights played out between say Ferrari and McLaren when it was a foregone conclusion that the two teams would be out front hoovering up the big points positions and race victories.
This championship run-in is different because the relative performances of several teams are very close and unpredictable with McLaren, Ferrari, Red Bull, Williams, Brawn, and Renault regularly in the points and even the podium.
This helps Button providing the other teams are not between him and Red Bull. Or his team-mate, as happened in Valencia.
Button has not had a reliability issue yet this season, whereas some of his rivals have - most significantly Vettel, who may well have to take a grid drop in the closing stages should he take a ninth engine.
It would also be so easy for Jenson to tangle at La Source hairpin in Spa this coming weekend, or get caught out by a rainstorm at the Japanese Grand Prix at Suzuka. But so could the others.
It will be interesting to see which teams can create a good aero package for the one-off high-speed Monza layout too. That race will be very important.
The one confidence booster that Button can take home from the European GP is his race pace - he's still fundamentally one of the very fastest drivers on the grid. He can still win the drivers' championship comfortably if he keeps his head and can sort out his qualifying pace.
It would have been painful for him to take part in the team post-race photo shoot on Sunday to celebrate a jubilant victory for Barrichello. But will that represent a powerful motivation tool or just more pressure?
The victory will boost the Brazilian; he is right back in contention for the championship. Had the result been reversed, Barrichello would surely have been duty bound to offer his support to Button for the remainder of the year.
Instead he is now the main enemy from within, which will take some handling with the inter-team politics. As Red Bull boss Christian Horner pointed out, even more pressure has been added to Brawn's equation.
It was a dark day for Red Bull, the championship's other main protagonists.
Brawn won 12 points in the constructors' race and Barrichello leap-frogged Webber for second in the driver standings.
To make matters worse for the Australian, who very honestly said that given his pace he got the result he deserved, he didn't score any points to cement his gap over his team-mate Sebastian Vettel.
The worrying thing about Webber is why was he so far off the pace? He was never properly fast at any point and I heard that he was so disappointed and angry after the race that he could hardly speak.
This week we move on to the Belgian GP. There's lots of surmising about which track suits which car, but I don't buy into all that because the key teams are relentlessly developing their packages and they are so close anyway.
What is clear is that Brawn has rediscovered its speed from earlier in the year, which is significant.
Martin Brundle was talking to BBC Sport's Sarah Holt.