Well i think in a game of Gormball you need luck & maybe a bit of skill. The best character to play with is 'Thyassa the Chia' He is ranked #1 in the world, And this might be true i think 70% of the time you might win. plus you will never get knocked out on the first go.
Secret: Pick a character then start playing. when its your go to enter how long you want to hold the ball. enter 1 second and hit throw. When the new screen comes up, hit the back button and enter in 5 seconds. do this everytime on your turns. What this does is the computer thinks your opponents are holding the ball for 5 seconds and you only hold it for 1. may help you win. i'm not that certain but hey give it ago.