Board Thread:Dragon City Gameplay Questions & Answers/@comment-13428995-20130808021209/@comment-11535585-20130808043952

It's fine to lose, you still get to beat 10 and level up the rank. If you're worried about not being able to move up to the next league, don't worry. The island will rotate so that you can fight a different opponent (which you have beaten before). The island rotation may take hours or a day or two, but it will.