A tournament is over at 12 wins or 3 losses. Each win in a tournament will increase your final reward.
In a tournament, you may only use a booster one time. After using a booster, it will be blocked for use in the same tournament unless you use coins to unlock it.
Common boosters can be unlocked for 50 coins, Rare boosters for 100 coins, and Epic boosters for 150 coins.
Three boosters are always available, namely First Aid, Freeze Time and New Hand. Your Energy is not consumed when you play a tournament.