Japan have high hopes of finally banishing a 20-year World Cup win drought when they face Pacific islanders Tonga in a battle of the Pool A minnows on Wednesday. Opening defeats to France and New Zealand have left Japan\'s coach, legendary ex-All Black John Kirwan, undaunted as the Brave Blossoms seek to end a barren streak stretching back to 1991.Kirwan believes Asia\'s top-ranked side are capable of two wins at this World Cup with games to come against the beefy Tongans in Whangarei, followed by redoubtable Canada in Napier on October 1.Two wins -- which would triple their all-time haul after 1991\'s 52-8 triumph against Zimbabwe -- would make good on Kirwan\'s bid for Japan to be the \"most improved\" team as they look ahead to hosting the World Cup in 2019. \"Just one will do. A one-point difference will do. This is not about how much we win by, tomorrow is about playing to our potential,\" Kirwan said on Tuesday. \"If we do that it will be a game and a half, and it will come down to something little. We have to be ready for that.\" Kirwan, who is ambitiously targeting a top-eight ranking by 2015 and a place in the 2019 final, announced 10 changes for the game as he reverted largely to the team which battled bravely to a 47-21 loss to France in Japan\'s opening match.Try-scorer Hirotoki Onozawa is the only surviving back from Friday\'s rout, while the backrow trio of captain Takashi Kikutani, Michael Leitch and Itaru Taniguchi are all retained along with second-rower Toshizumi Kitagawa. Tonga also look out of the running for the quarter-finals after last week\'s surprising defeat to Canada left them with just one bonus point from their opening two games. The 25-20 reverse disappointed thousands of Tongan fans in Whangarei, and newly appointed captain Aleki Lutui said the team owed their supporters to make amends against Japan.\"There is a lot of people to play for, not just us, but our supporters. We have to do something for them,\" Lutui said. Tonga coach Isitolo Maka made eight changes from the Canada game as he returned to the core line-up which denied the All Blacks possession for long periods of the World Cup\'s opening game on September 9.Maka\'s brother Finau, the usual captain, was ruled out with a rib injury while Taniela Moa was named at scrum-half with Kurt Morath at fly-half. The two teams have never met in the World Cup but Japan holds the edge 7-5 in their other encounters and narrowly won 28-27 when they played at the Pacific Nations Cup in July. Both sides have a distinguished record in qualifying for the World Cup but Tonga have never reached the quarter-finals in five attempts and ever-present Japan have just one win in 22 games, alongside 2007\'s 12-12 draw with Canada.\"Tomorrow\'s going to be a battle, physicality. It\'s going to be scrum, it\'s going to be ruck, it\'s going to be defence,\" Kirwan said.\"If we think too far ahead, we will get beaten. Tomorrow is our last game, and that\'s how we need to approach it. The next day, we\'ll get up and go again.\"