15GOKU NEVER DEFEATED AN ANDROID
At least in canon. Goku is the hero of the Dragon Ball franchise. He’s defeated nearly every villain he’s come across, except when it comes to the Androids. During the Android Saga, Goku is surprisingly absent, bed-ridden on account of a heart condition. Before that however, Goku fights Android 19
and loses rather badly. He’s unable to keep up with the android and is himself weakening on account of his heart condition.
Even after the androids are no longer the show’s central threat and the antagonist switches to Cell, Goku is once again unable to claim victory; Goku stalemates Cell. The only reason he fought the android was to give his son Gohan a chance to see how Cell fought and formulate a plan to defend himself against the monster. Goku also never has a chance to battle either 17 or 18 since Cell absorbed them.