The Merseysiders slumped to a loss in front of a packed crowd at Boston's Fenway Park as goals from Michael Bradley and Alessandro Florenzi helped the Italians to a 2-1 win
Second-half strikes from Michael Bradley and Alessandro Florenzi proved to be enough for the Giallorossi, despite a late effort from Reds midfielder Charlie Adam.
Liverpool boss Brendan Rodgers opted for a relatively youthful starting line-up with Raheem Sterling and Nathan Eccleston both involved up front, while experienced heads Martin Skrtel, Jamie Carragher and Joe Cole formed the spine of the side.
Veteran playmaker Francesco Totti and striker Pablo Osvaldo started for the Italians as Zdenek Zeman named a strong starting XI.
Roma had the better of the early going and created the game's first real opening as Panagiotis Tachtsidis shot straight at Peter Gulacsi.
The Reds quickly grew into the contest and came close to taking the lead when Sterling was denied from close range by Romanian keeper Bogdan Lobont. Liverpool were soon back on the defensive, however, as Gulacsi had to be called into action to turn an Osvaldo effort round the post after a fine break from the Italians.
Midfielder Jonjo Shelvey was at the centre of the majority of Liverpool's attacks in the first half, and the 20-year-old almost netted a spectacular solo goal as he beat several Roma defenders before his shot was tipped away by Lobont, Eccleston followed up but his strike flew high and wide.
Liverpool continued in the ascendancy and fashioned the best chance of the opening period as Alberto Aquilani's ball over the top found Cole. The former Chelsea man showed great awareness to try and chip the ball over Lobont from long range but his effort bounced off the top of the crossbar.
Despite a glut of substitutions during the interval, the game continued to be played at a surprisingly fast tempo. The deadlock was nearly broken three minutes after the break when substitute keeper Brad Jones produced a fine save with his feet to deny Tachtsidis from outside the box.
Fourteen minutes later, the Serie A side did take the lead as USA international Bradley turned smartly inside the box before firing a low shot past Jones and into the bottom corner.
Roma's advantage was quickly doubled as a fine move was finished off by Florenzi, who rolled the ball into an empty net after latching onto a flick from Erik Lamela.
The Giallorossi appeared to be cruising to victory, but 10 minutes from time Liverpool gained a foothold in the contest as Adam fired in from the edge of the box after collecting a pass from Daniel Pacheco.
That goal proved to be little more than a consolation, however, as the Reds were unable to mount any kind of an incisive attack in the closing stages, condemning Rodgers to a first defeat as he continue preparations for the new Premier League campaign.