Button set to blow title bid - Horner

If Jenson Button was not already feeling the pressure of his diminishing points lead, he should not read Christian Horner's latest comments.

With Sebastian Vettel and Mark Webber both in the fight to hunt down the Brawn driver for the championship, the Red Bull team boss likened Button's situation to a soccer player about to blow an important match with a penalty shot.

"I'd be a worried man if I was him. Wouldn't you be? At the moment he is like Stuart Pearce taking a penalty. You can see he (Button) has tightened up since (winning in) Turkey," Horner said.

Scarcely attempting to hide the attempt at psychological mind games, the Briton directly questioned his countryman's ability to handle the stress of capturing the 2009 drivers' crown.

"I have known Jenson since he was 11. He has won a lot of races but not many championships and finds himself in uncharted territory. He is inexperienced at being the favourite," said Horner.

He said that if he had to place a bet based on street-fighting qualities, he would back Button's rivals to win the championship.

"It's down to mental strength at the end of the day. It's like the top 25 tennis players. They can all play the strokes, it's who wins the big points. It's the same in any sport," said Horner.

Button's boss Ross Brawn confirmed that he has sensed a change in the driver since the easy-riding of earlier this season.

"It's ten years or more since Jenson fought for a championship or more, so he's having to re-engage his thoughts on fighting for it and what I see is perfectly normal. I don't see anything negative about it," he said.