I am not sure if this still works, but a long time ago, the cup/B3 money is given to the team immediately after the game started (or 15 minutes before the game starts). It is then taken away after a short time and given back after the game. So you can refresh your economy page to find out if you win. If I recall correctly one B3 champion (Venomous Scorpions?) was able to find out he won B3 using this.