(Explanation:Ultra and Vegeta trained with each other over the 7 years which made Vegeta far stronger than normal.)
Majin Vegeta,still in base form,was about equal with the dead Super Saiyan Goku as they fought.Then the Mind-Controlled Saiyan went Super Saiyan and began rather easily overwhelming the dead Super Saiyan that dared to insult their pride.Son Goku then went Super Saiyan 2 and so did Majin Vegeta,and Goku had to use all of his skill just to barely avoid attacks from the now Majin Vegeta.The strongest pupil of Roshi thought,'Damn,I'll have to go Super Saiyan 3 to win this!' And then he began powering up,the energy knocking SSJ2 Majin Vegeta to the ground.Now a Super Saiyan 3 stood before the corrupted Super Saiyan 2 and Goku said,"Sorry I didn't show this earlier...I don't use this form much." Then their brutal battle continued,noses being punched and kicked in and many other injuries occurring.Eventually an exhausted now base form Goku tried to use Kaioken to overwhelm the exhausted SSJ Majin Vegeta,but Vegeta used a Big Bang Attack,and said energy blast slammed into an mountain,an now unconscious Goku stuck to the wall of the mountain.