Italy overcame a determined effort by the United States to claim a 27-10 bonus-point victory on Tuesday and set up a Pool C decider against Ireland for a first rugby World Cup quarter-final berth.
The Italians ran in the opening try in the third minute at Nelson's Trafalgar Park thanks to captain Sergio Parisse but the US fought back, with fullback Chris Wyles crossing and converting to level the scores 10 minutes later.
The Italian pack proved too strong throughout the match as first five-eighth Luciano Orquera and prop Martin Castrogiovanni crossed for tries in the first half.
The Italian pack then forced a penalty try with 15 minutes to go to claim the crucial four-try bonus point.
Italy face Ireland in their final Pool C match in Dunedin on Sunday with the Azzurri needing a victory to make the knockout stages.
Scorers
Italy: Tries: Sergio Parisse, Luciano Orquera, Martin Castrogiovanni, Penalty try. Conversions: Mirco Bergamasco (2). Penalty: Bergamasco.
United States: Try: Chris Wyles. Conversion: Wyles. Penalty: Wyles
Referee: George Clancy (Ireland).
