For the fifth year running, Atlas F1 is going to keep an eye on the battle between teammates throughout the season with a simple measurement: we compare the qualifying times of each driver against his teammate's result. After every Grand Prix, we will show how teammates have fared up against each other, and where they are overall since the beginning of the season. At the end of the season, the World Champion of Qualifying Differentials will be elected - the driver who beat his teammate by the most seconds. Only those who participate in at least 15 of the 17 rounds are eligible for the coveted crown; and for those who made the efforts and participated in all 17 races, the best and worst result will be scrapped.

With four qualifying sessions completed for 2002, the differentials are once again on a roll! Let's see which drivers deserve bragging rights.

San Marino Notables

• Setting the Record Straight: Jordan's Takuma Sato had his best qualifying position ever, while McLaren's Kimi Raikkonen qualified in fifth for the 4th time in a row, so once again he equaled his best qualifying position ever.

• The Excuses: Giancarlo Fisichella had to use his spare car for qualifying, perhaps explaining why he was outqualified by newcomer Takuma Sato.

• Changes since Brazil: There are no changes in the overall averages, however with Sato outqualifying Fisichella, only Mika Salo, Heinz Harald Frentzen and Mark Webber remain unbeaten by their teammates this year.