The Spaniard set a sensationally-quick lap time of 1:21.962 at the start of Q3 which could not be matched by his rivals, and Alonso even had the luxury of not requiring a second flying lap.
Jenson Button took second for McLaren, out-qualifying team-mate Lewis Hamilton to split the Ferraris, as Felipe Massa qualified third.
Red BullÃ¢â‚¬â„¢s Mark Webber was forth despite an engine failure towards the end of final practice this morning, ahead of championship leader Hamilton, and team-mate Sebastian Vettel.
Nico Rosberg won a tight battle to finish seventh ahead of WilliamsÃ¢â‚¬â„¢ Nico HÃƒÂ¼lkenberg, with Robert Kubica and Rubens Barrichello rounding out the top 10.
Adrian Sutil was unlucky not to make the final qualifying run after a late run from Rosberg dropped Sutil to 11th. Fellow German Michael Schumacher could only manage 12th in his Mercedes, ahead of Japanese rookie Kamui Kobayashi and SÃƒÂ©bastien Buemi.
Predictably, the three new teams were the first to bow out of qualifying, along with Force IndiaÃ¢â‚¬â„¢s Vitantonio Liuzzi who suffered mechanical problems, with LotusÃ¢â‚¬â„¢ Jarno Trulli 18th ahead of team-mate Heikki Kovalainen.
So far this weekend, all three leading teams have shown they have the pace to win at Monza, but SundayÃ¢â‚¬â„¢s will inevitably come down to the best aero package combined with a solid race strategy.
McLarenÃ¢â‚¬â„¢s drivers have opted for different set-ups with Button reportedly keeping the F-duct system; while Hamilton had his removed ahead of final practice. Early indications suggested both packages were quick for McLaren, and it could lead to an interesting in-house battle as to who comes out on top.
Incredibly, AlonsoÃ¢â‚¬â„¢s pole is his first for the Scuderia since switching from Renault, and FerrariÃ¢â‚¬â„¢s first in 30 races. The Italian teamÃ¢â‚¬â„¢s last pole came at Felipe MassaÃ¢â‚¬â„¢s dominance of the season-ending Brazilian Grand Prix in 2008 – a race more famous for Hamilton securing the world championship on the final corner as he finished fifth despite Massa already taking the chequered flag.
The Italian Grand Prix is live in the UK on BBC One, BBC 5Live, and the BBC F1 website, with the race starting at 1300BST.
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BIOGRAPHY: Cesc Fabregas