As the battle for the Formula One drivers' title enters a riveting finale in the last four races with only 12 points separating the two contenders, watch out for the dirty tricks.

In the last two races, Fernando Alonso, the series leader, and Michael Schumacher, in second, drove to the limits of aggressiveness, and both were even penalized for infractions in practice at one of the races.

But the play is not confined to the track. In preparation for the Italian Grand Prix at Monza on Sunday, each driver in an off-track psychological game this week vaunted his chances of winning the title. Alonso said he wanted to beat Schumacher on Ferrari's home ground, while Schumacher said, "Our strategy has to be attacking."

But where is the line drawn between attack and dirty driving?

"You know the rulebook: It's blank," said David Kennedy, a former driver from Ireland who is now a television commentator. "You get away with what you can get away with."