USA scrum-half Mike Petri has told Sports Mole that he is confident his side can push on following their disappointing Rugby World Cup campaign.

The Eagles ended their participation in the showpiece tournament with a 28-18 defeat against Japan on Sunday to make it fours defeats from four in Pool B.

Petri believes that the United States can continue to improve, however, in order to give an improved showing in four years' time when the competition heads to the Far East.

"It's a process that is going to take time; some guys will come back and others won't," he said. "There are others in this group also who are really going to step up and help lead this side over the next four years."

The Brooklyn-native also reserved some special praise for opponents Japan, who themselves bowed out despite winning three of their pool-phase matches.

"The Japanese have had a great tournament," he continued. "They play a fantastic brand of rugby and we knew going into it that they were going to be clinical and they were.

"They stepped up to the plate in every game, so credit to them. Japan really made a statement at this tournament and probably turned a few heads in the process."

Uruguay are the only other side to have exited the World Cup without a single point to their name.