I thought about 7 situations in case you win a tournament against a champion
1. The champion and everyone congratulates you
2. The champion is impressed and wants to join your clan
3. After the tournament, someone comes to congrats you and tells you to join him to a feast in your honor, you follow him but it's a trap. They try to kill you or just threaten you.
4. You are attacked in the streets by the gang the champion is in
5. The champion tells you that it is he's job and he needs it to survive. if you win against him again you put his family and himself in financial danger. winning against him again and you lose honor unless you give him money.
6. you sleep in the city and during your sleep you attacked by an assassin hired by the champion
7. you are invited by the campion for a drink, he offers you a lot of money is you lose willingly in a public duel.
Some more:
- One of the tournament contestants marvels at your skill and approaches you afterwards, asking to join your warband.
- A gang leader is impressed by your skill and asks if you'd like to provide him some muscle.
- A lord comes to you, asking if you would be up for a bit of provocation against your neighboring nation. He wants you to attend X tournaments in their land, flying your home coat of arms and provoking the crowd. Once finished, this should provide a very small push towards declaration of war.
- A peasant comes to you, pleading for help with a problem in his nearby village. He has come looking for someone to train the men there, and you have proven yourself a worthy candidate.
- The arena master takes notice of your skill at arms and charm over the crowd. Good competition will lead to good profits. He asks to sponsor you, paying for each tournament appearance in the city for the next month.