Italy start an intense run to the pool-play finish line with no margin for error in their \"win at all cost\" clash with the United States on Tuesday. A four-try, bonus-point victory will set them up for a winner-takes-all group finale against Ireland on Sunday to determine the second Pool C quarter-finalist along with the seemingly inevitable entry of Australia. It\'s also a must-win game for second-tier side the US Eagles, who have already beaten Russia, and a second win could earn them direct entry to the 2015 World Cup without the need to go through qualifying tournaments. Ireland, Italy and Australia remain in contention for the two knock-out berths with Australia in the strongest position as they only have minnows Russia left to play. Italy coach Nick Mallet was impressed with the way the United States did not weaken off in the second half when they lost to Ireland 22-10, and was taking no chances by naming his top side. The battle-hardened front row of hooker Leonardo Ghiraldini and props Martin Castrogiovanni and Salvatore Perugini have been tasked with taking control up front and \"it won\'t be easy,\" Castrogiovanni admitted. \"They rested their best players against Australia to be ready for this match. They want to win their second match at a World Cup, because it is something they have never done before.\" In the backs, the premier centre pairing of Gonzalo Canale and Gonzalo Garcia are reunited as Italy look to score wide, although they have lost the thrust of fullback Andrea Masi who pulled out on the eve of the game with a thigh strain. \"We know about the points and bonus points and so we want to score four tries (against the United States) and go into the last match against Ireland with confidence and a chance to qualify,\" said captain Sergio Parisse. That has caused a dilemma for Mallet who does not want to flog his star players, with only a five-day break before playing Ireland, but he cannot afford to substitute them if the United States put up a bold showing. \"Obviously, I\'d like to do that, to allow them to only play 60 out of 80 minutes, but if the game is really tight, which it could quite easily be against the United States, I think that it\'s difficult to do that because we must win at all cost.\" The US Eagles sacrificed themselves in the 67-5 hiding by Australia, resting 14 leading players, including captain Todd Clever, so they would be fresh to play Italy. The 14 are all back in the fold to play Italy and while coach Eddie O\'Sullivan has given his side every opportinity to create history by winning a second match he is also realistic. \"I\'m not saying we\'ll beat Italy, that\'d be an arrogant thing to say, but I think we can test Italy and see what they\'ve got,\" he said. \"We know we\'re on the flight home on Wednesday morning so if we can turn in another big performance against a tier-one nation, as we did against Ireland, that\'d be a perfect way for us to finish our World Cup.\"