CHONGQING, China, July 28 (Reuters) - Iran booked a spot in the Asian Cup quarter-finals on Wednesday after holding Japan in an absorbing 0-0 draw. Three-times champions Iran finished on five points, two behind holders Japan in Group D. They will play Group B winners South Korea on Saturday while holders Japan face Jordan. Iran, who only needed a draw to secure the group runners-up spot, were missing three suspended players but still created the better chances in sweltering Chongqing.