Superman faced a defeat more devastating than Doomsday in Action Comics #1037. When his new team, the Authority, finally reached War world to free everyone they were utterly defeated and humiliated by Mongul.
With the Authority powerless Superman was thrown in with the rest of Mongul's slaves. When Midnighter, the only member of the team who managed to escape capture, came to rescue him, The Man of Steel didn't want to be saved.
Superman explains that, although they clearly went through an unexpectedly catastrophic defeat, this situation is the best thing he could have asked for and drew a symbol to trust him.
Now that he's amongst those who believe the despotic dictator's twisted lies, he can work on getting them to believe in his truth instead of their evil ruler's.
This is an example of Superman using his real power. Though most focus on the hero's incredible abilities of strength, speed, flight, and everything else in between. Superman's real power is the way he gets people to believe in him.
Midnighter, however, isn't convinced. Superman may be where he wanted to be but he brought a whole team with him. Thanks to his recklessness, Lia Nelson is dead and Apollo will soon be next.
So, What do we learn from this? Sometimes losing is a good thing if we can get more out of it, and be able to save everyone.