A top field which included Brits Mark Cavendish and David Millar, had plenty of attacks as the race of 284km neared its completition.
Garzelli, Michael Rogers, Vincenzo Nibali and Flippio Potazzo all forced the pace but with less than a kilometre to go, it was down to a 25 man bunch sprint.
Spain's Oscar Friere was the man who surged across the line with Tom Boonen second, followed by Petachi, Modolo, Bennati and Hushovd.
Mark Cavendish finished 89th with David Millar 105th, Jeremy Hunt was 142nd whilst Roger Hammond and Team Sky's Ian Stanard did not finish.