The Eagles were unable to get off the mark at the competition in Sunday's final outing, as their opponents proved too strong and recorded a 28-18 victory.
Despite the disappointment of returning Stateside without a point, Kelly was still quick to find some positives.
"We put in a full 80 today, unlike at other times in the tournament," he told Sports Mole. "Certain mistakes may have cost us at times, but it was probably our best performance of the tournament."
USA join Uruguay in failing to register a single point from their four pool-stage fixtures.