Huitzilopochtli sprung from his dying mother's womb, dressed in full battle regalia, then proceeded to behead and then dismember his older sister (who killed said mother), and lobbed her head into the sky, creating the moon. He then repeated the process on his four hundred other siblings, creating the stars (either he diced them into smaller chunks or improved his throw). Yeah, the Aztecs didn't just worship ANY god.
In Hindu Mythology: When Garuda steals Amarita from heaven, various gods try to stop him and get their asses kicked. Notably, when Indra strikes Garuda with the Vajra, it doesn't even scratch him. However, Garuda drops a single feather to show his respect to Vajra (it was Shiva's gift to Indra). It takes Vishnu to fight Garuda to a draw. And he did all of that before gaining godhood.
Evoked in the Eldritch Abomination page, but it needs to be retold here. How does Zeus get rid of Typhon, the most powerful monster in the Greek mythology ever, who by himself could single handledly smack the gods around ? BY CLUBBING HIM WITH THE ENTIRE ISLAND OF SICILY.
Achilles' life is one long Crowning Moment of Awesome, since he chose a short glorious life (and eternal fame) over a long, quiet one. Highlights include his defeat of Hector and killing the Amazonian Queen Penthesilea.
The Twelve Labors of Heracles were a number of separate Crowning Moments of Awesome that were eventually linked into a single narrative.
Empress Jinguu of Japan, due to her husband's stupidity, had to conquer Korea in his place. While pregnant. What did she do? She tied her belly up in a particular way as to prolong the pregnancy and personally led her armies into battle, then had her child after the war.