2. 1-5 draw lots. See you if:1-4,2-3,5; If 1, 3 wins, draw with 5; if 1-5, 3 draws, see you later; If 1 still wins, then hit 3 to decide the outcome, if 1 wins;
3. Similarly, 6- 10 draw. According to the above steps, if 6 wins;
4. The first group champion 1 and the second group champion 6 compete to decide the champion.
I don't know if it suits you.