Piccolo vs Goku and Vegeta
So after Piccolo fuses with Kami, he decides he's got enough power to do what he wants with Earth. So instead of going after the androids, he decides to first take out Goku and Vegeta.
Ssj Goku as seen upon his return to Earth (healthy, no virus)
Ssj Vegeta as seen in his fight against Android 19
VS
Piccolo as seen in his fight against #17
If Piccolo puts them both down, Ssj Trunks as seen vs Mecha Frieza comes into the fray.