More than 17,000 watched on as the Americans struggled with 13 men in the second half following red cards for Andrew Suniula in the 44th minute and Paul Emerick in the 65th minute.
However, the Azzurri were already in the lead before either player was dismissed, with Carlo Festuccia capitalising on a botched line-out to score the opening try just three minutes in.
After the teams traded penalties, the United States tied the match when Emerick scored their only try in the 27th minute.
But Italy responded quickly, first with a penalty and then a try from Edoardo Gori to go 20-10 up before half-time.
Things then began to unravel for the Americans, with Suniula dismissed for a late hit on Riccardo Bocchino and then Emerick seeing red for a shoulder charge.
Italy took advantage in the final 15 minutes with Bocchino slotting another penalty before Kristopher Barton capped the win with a 77th-minute try.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
$29.99
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.
