Barely. Most basic monsters die, Papyrus and Toriel take serious injuries, but after Asriel's intervention around the half of the battle, yeah, they do win.
This AU happens in a Neutral Route. After hundreds of Pacifist and Genocide runs, everyone in the underground decides to finally take out Frisk. Like, literally EVERYONE! From Toriel and Flowey all the way to Gaster and Chara! That's why it's called "Payback Route", as it's kind of a culmination of the original timeline.
Link to this sequence: 2795225
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Undertale: Payback Route - Final Act (WIP) by Syllue