How do you beat vegeta great ape in dragon ball z ultimate tenkaichi

are you talking about the part where you press b rapidly...cuz i had my sister do it...she is faster at button mashing than i am.. to beat him in the first stage shoot him with energy while dodging his attacks. when he attacks dash to the side at the last moment.(not too late though)then after some interactive cutscenes, the second stage starts...its the same as before except he uses melee combat on you...when he slams his fists in the ground, attack them