Just to clear it up, Goku is not actually a Super Saiyan, despite what Vegeta might think. Goku is just more powerful, due to his rage pushing him to new heights. He's in an Super Saiyan-like state, a False Super Saiyan.
"His power level! 58000!" screamed the Saiyan prince. "Nappa, you idiot! You've let him become a Super Saiyan!"
This brought Nappa back to reality. He dropped Gohan's limp body, turning to Vegeta. "Wha-"
Nappa could not, however, finish his sentence. Goku had, in one motion, approached Nappa, punched him in the back of the neck, and caught his son in midair. It didn't matter, though, because Gohan was dead.
A weak gasp escaped Nappa's paralyzed body, no louder than a hiccup. Vegeta glared at the Saiyan's broken body, and then at Goku.
"So, you seem to have defeated my partner." stated Vegeta, not seeming to care about Nappa's defeat.
Wow, you noticed." mocked Goku, "If you'll excuse me, I need to talk to my friend."
"Oh, you mean Baldy?" laughed Vegeta, "Yeah, he was quite the pest. Impressive how he survived so long, considering his uselessness!"
Not bothering to respond, Goku approached Krillin.
"Krillin, I need you to leave."
It was a simple statement, and Krillin understood perfectly.
"Alright, Goku. Do you want me to tell Chi-Chi, or-" Krillin began, hoping that Goku would say no. Even after his encounter with the Saiyans, Krillin still feared that woman.
Goku cut him off. "I'll tell her myself."
Krillin gave him a nod, before flying off to Kame House.
Goku walked towards Vegeta, staring into his eyes.
"Shall we?" asked the Saiyan prince.
"Yeah." said Goku. "I'd just love to beat the shit out of you."
Vegeta chuckled in response, but he was not as calm as he acted. Inside his head, thoughts were brewing madly. "I can't beat him in this state. If I can stall long enough for the moon to come out..." he thought, darting his eyes around the sky.
"What are you doing?" questioned Goku impatiently.
"I'm just waiting for you to make your move." replied Vegeta.
The 2 fighters stared at one another, both of them sure that they would be the victor. On a whim, Vegeta sprang towards Goku, preparing to land a punch. It never connected, because by the time Vegeta had approached him, Goku had driven a fist into Vegeta's mouth, causing blood to drip down Vegeta's mouth and chin.
Vegeta put a hand to the area of his face that hurt, which was essentially all of it. "Uurggh! How dare you defile the face of a Saiyan elite! Do you think you could defeat me?!"
"Yes." said Goku flatly.
This really set Vegeta off. "You...scum! I'll show you what happens- when you toy with Prince Vegeta!" he yelled, swinging his arm towards Goku's head.
One second later, Vegeta felt a horrid throbbing pain in the middle of his forearm. "Damnit." he thought. "At this rate, I'll be beaten in a matter of minutes! I need to think of a plan..."
Vegeta flew several meters above and behind Goku, and began charging his next attack.
"So, what have you got planned now?" asked Goku.
"Oh, you know. Just a little bit of my GALICK GUN FIRE!" Vegeta screamed as he launched the purple beam of energy in Goku's direction.
When the attack hit, a ring of fire and Ki surrounded Goku, forming thick clouds of dust everywhere. Vegeta smiled, but his expression quickly faded when the dust cleared, and Goku was seen without a scratch on him.
"How neat. Since it's my turn, I'll think I'll use my Kamehameha." stated Goku.
"Kamehamewhat?" asked Vegeta, before being propelled into the sky by Goku's blue wave of Ki.
After he was able to catch his breath, Vegeta assessed the damage done to his body. He definitely had broken both shoulders, a couple of teeth had been knocked out, his kneecap was out-of-place, and he was pretty sure that he had a black eye or 2.
Luckily for him, though, he still had his tail.
"Now, if I can just find the-" thought Vegeta, before stopping due to surprise. "What the hell! Where did the moon go?! It's late enough for it to come it, where is it!?"
Little did he know, a certain Namekian had taken care of the moon problem months ago. He assumed, however, that Kakarot had done it. Of course, none of that mattered, because Vegeta knew how to create his own moon. And, boy, wouldn't he love to see the look on Kakarot's face when he does.
Goku was looking up at the sky, waiting for Vegeta to come down. "Come on, you bastard." he thought, "There's no way that attack killed you, so come on down..."
Goku's requests were fulfilled, as a smug-looking Vegeta came down from the sky soon after.
"You probably think you were so clever by destroying the moon, huh, Kakarot?" asked Vegeta.
"What are you talking about? I've been dead for a year, when would I have time to do that?"
"Whatever, Kakarot! It doesn't matter, because us elite Saiyans know a method of creating artificial moons!" Vegeta bragged, as he formed a whitish-bluish orb in his right hand.
"Now, watch! Watch as you witness your destruction!" he yelled, launching the orb into the sky.
Seconds later, Vegeta began to undergo a transformation. He started to grow hair all over his body, taking on the appearance of some sort of man-ape. Soon, after his entire body grew in size tremendously, along with his elastic armor. In no time at all, Vegeta was a large hairy beast, and he towered over Goku.
"Hahahaha! Try and beat me now, Kakarot!" laughed the Great Ape Vegeta.
Goku, with no other instinct, brought his arm back, produced a Ki attack, and rapidly shot his arm forward, launching a beam at the monster. It bounced off harmlessly, being about as effective as you would expect a handgun to be against Godzilla.
Vegeta, laughing madly, captured Goku in his hands, and held him high up in the air. "Any last words, Kakarot?"
"Yeah. Kaioken!" Goku yelled, a red aura surrounding him.
Goku began to struggle in Vegeta's grip, but to no avail.
Vegeta simply laughed again. "Still not strong enough, sorry!"
"Damnit." Goku thought, "I could use the Level 2 Kaioken, but I'm not sure my body will be able to take it. On top of this "Super Saiyan" thing, the extra energy could tear my body apart." He began wrestling in the ape's hands, desperate to escape his death hold.
Vegeta took a hold of Goku's head with his thumb and forefinger, ready to crush the squirming Saiyan's skull.
"Now" said Vegeta, "I'll ask again. Any last words?"
"Yeah. Destructo Disk!" said a voice in the distance, launching a razor-sharp disc of Ki, aiming directly at the Saiyan's tail.