Yup, and given that in vanilla UFO, you are guaranteed a sectoid research mission in the region of your base, chances are that the first UFO you shoot down is a sectoid one. On superhuman, that's 20% chance of a retaliation and retaliations are the same race as the one that was shot down, so it will be mind control + cyberdiscs. Fun times!
Always order flamethrowers, rocket launchers, big rockets and HE packs on day one, so hopefully they arrive in time for the potential base defence. And some soldiers/dogs to replace early losses and help out defending!
In fact, mods like the FMP really help by giving you access to a pretty reliable close range answer to cyberdiscs which is perfect for base defence: Flamethrowers hiding in a closet and peaking out to BBQ cyberdiscs. With that, you don't need to worry about them blowing up, or having to get large rockets/HE packs on them and potentially putting soldiers at risk or damaging valuable loot.