Please indicate your character's prowess in wrestling so I have an idea how to write this. I've added Matrim to make it a clean 8 wrestlers. Here's the order
Garstan v Stigend
Matrim v Crabannan
Dan v Harreld
Aethelstan v Osmund
Two of these initial rounds are easy, since Crabannan has a bum leg and Harreld has a huge advantage on Dan ... once he can get his hands on him.
The winner of G v S will face the winner of M v C, and D v H will face A v O; then the finish round will be the between the winners of the those two rounds.