Intentionally allow one of your members to die at the final battle. For example, if you allow Kulilin to die (as in the story)
Goku will get angry. He will flash, then turn into a Super Saiyan (BP: 4999999). If you give him a BP increase-card, Saityouruu worth 30 pt, his BP will reach 7999999. Goku cannot use his kaikouken. Note: Do not allow Vegeta to die, you will fight him after you defeated. Freeza may also become Super.