Teammate and Championship Leader Jenson Button came in second, completing Brawn's fourth (and last) one-two finish of the season, while the Ferrari of Kimi Räikkönen came third after reigning World Champion Lewis Hamilton crashed on the final lap.
Adrian Sutil, who finished in fourth place, recorded the first fastest lap of his career, and the first for the Force India team.
Fisichella became the first Italian since Ivan Capelli in 1992 to race for Ferrari at Monza, after terminating his Force India contract.
[5] The first session of the Italian GP finished with the McLarens on top with Lewis Hamilton and Heikki Kovalainen first and second fastest, respectively.
[6] Fischella, driving for Ferrari for the first time in his career, finished eighth ahead of teammate Kimi Räikkönen who ended the session in tenth.
Championship leader Jenson Button ended seventh while his Brawn teammate Rubens Barrichello finished twelfth.
Five minutes into the session Liuzzi ran off the track but did not damage his car and managed to proceed through to the next part of qualifying.
Very soon afterwards Hamilton set the fastest lap, while Webber, Alonso, Sutil and Räikkönen traded second place.
Heikki Kovalainen, on a one-stop fuel strategy was overtaken by the similarly fuelled Brawns of Rubens Barrichello, off the start line, and Jenson Button, through the second Lesmo.
Championship contender Mark Webber was spun by Robert Kubica at Della Roggia on the opening lap and was forced to retire.
[12] Before this, on lap 9, Kubica was shown the black flag with orange circle because he damaged his front wing during his contact with Webber, meaning he was summoned to the pits to repair it.
Sutil was able to keep up with the Ferrari driver throughout the race, but couldn't get close enough to pass as a result of turbulent air through the final corner.
Fisichella's replacement at Force India, Vitantonio Liuzzi, retired with a mechanical problem while challenging for the points.
[15] Barrichello admitted he was relishing the prospect of a straight title fight after playing second fiddle to Michael Schumacher whilst the German won five world championships at Ferrari.
[16] Webber admitted frustration at his first non-finish of the year following such a "small" accident, while Vettel insisted his Championship chances were not over.
"[17] The focus of the F1 paddock after the race, however, was on the looming Crashgate hearing at the FIA World Motor Sport Council in Paris the following week.
This was to determine whether Renault had asked former driver Nelson Piquet Jr. to crash at the 2008 Singapore Grand Prix, to aid teammate Fernando Alonso ultimately win the race.