Still not tired after getting his upper arm ripped open

Goku teleported forward and slammed his elbow into 17's face, crushing his nose. A snap kick sent waves of pain through the teenager's leg. Goku raised his hand, and a golden ball of energy caught 17 full in the chest, sending him spiraling to the ground.

The cyborg looked down. His bandanna and part of his shirt were torn away. The blast had ripped through his upper arm, revealing the gleaming metallic implants that Gero had given him. His eyes wide, he turned to his sister. "A little help here, 18?"

- Bringer of Death Chapter 38

"I've been serious, sis. Now get over here and give me a hand!" 17 said. His sister paled as she realized that they indeed had reason to worry. 17 had never asked for help with anything or anyone before.

Goku interrupted. "You need to give up. Promise to live a life of peace, and maybe I'll let you live. Otherwise, come at me together right now and let's finish this. I won't hold back any longer." Peals of thunder from the gathering storm gave gravity to his voice. The first few drops of rain began…a gentle sprinkle.

"You don't scare us!" shouted 18, her voice raising in pitch. Try as she might, she couldn't conceal her fear. How was it that this stupid Saiyan was so much stronger than they were? She didn't understand.

"You're out of time," the Super Saiyan snapped back. "This is the end for you both."

The two cyborgs charged him simultaneously, the girl coming in high with a charged ball of energy and the dark-haired boy coming in low with his leg pulled back. Goku waved his arm, throwing out a kiai that slammed into 18 and sent her tumbling. 17's kick connected, but the Super Saiyan expertly moved with the blow and twisted his body around, smashing the cyborg to the ground with a double elbow strike. Thunder boomed overhead, accompanying the crash of Goku's blow. The thick clouds made everything grow darker by the second. The Super Saiyan light of Goku's aura shone all the brighter.

...

The boy and girl continued the all-out assault on the lone hero with renewed ferocity. Their endurance was incredible; try as he might, Goku couldn't catch his breath for long enough to do either of them any real harm. He had no way of sensing their movements, and his eyes could only follow one of them at a time.

- Bringer of Death Chapter 39