Unknown to Superman, Doomsday had faced and beaten Darkseid in single combat, even after withstanding the full effect of Darkseid's Omega Beams, and was laying waste to Apokolips. ... Likewise, even though Superman had killed Doomsday once before, he was unable to do so again.

Is Doomsday stronger than Darkseid?

If both Darkseid and Doomsday were to battle in the fields of Infinite Frontier, Darkseid would have the upper hand. Ultimately, Darkseid and Doomsday are much alike in terms of the level of threat. Superman would much rather fight any other villain than both of them.

Can Doomsday be defeated?

Doomsday can be defeated and killed, although even that is extremely hard and will require a superstrong opponent at his absolute best. So, he is technically not immortal – he can die.