TOKYO, August 31 (Reuters): Japan booked their place in the 2018 World Cup with an emphatic 2-0 win over Australia in Saitama on Thursday that took their Asian arch-rivals' hopes of qualifying for Russia out of their hands. Takuma Osano scored late in the first half before 21-year-old midfielder Yosuke Ideguchi covered himself in glory with a sumptuous finish in the 82nd minute as the Samurai Blue sealed a sixth straight appearance in the global showpiece. Japan are now assured of finishing top of Group B in Asian qualifying before their final match away to second-placed Saudi Arabia, a match that Australia will watch nervously. Third-placed Australia will need a handsome victory over Thailand in their final qualifier and hope Japan can beat or draw with the Saudis, who have a better goal difference than the Socceroos. Japan join Iran, Brazil and hosts Russia in the 32-team tournament, which will be held from June 14 to July 15 next year.