For starters, note all the nuances in the song. There's one part where the bass raises an octave and it's a dead giveaway of what to go for. It's a square with little sustain and gentle portamento on it. Sytrus has a preset that's really close to what you want (bassline square; just remove the fx knob and you got the bones of it).
I've been trying to remake the sound for your pleasure just to help you out, but I'm not all that good at that style of music. All i can tell you is that it starts off as a square wave and a low pass cut off to give it a donk sound.
Also add on a chorus to give it a good sound. Tweak it a bit to your tastes and do what you wish afterwards.