It's kind of amazing to see a relatively clear succession of events like this.
Miesha Tate, always a tough competitor, even champion pre Ronda Rousey, for skill and sheer tenacity most say, decided she lacked one thing:
Knocks down her opponent twice in Round 1.
Keeps training, keeps getting stronger, developing more punching power and overall upper body strength, even though she was top tier by fighting ranking before then ...
Enter the Janoskians:
https://m.youtube.com/watch?v=mf6SGfLs9cY
... and finally enter Holly Holm, who knocked out Miesha's greatest rival, and is actually bigger and taller than Miesha, if memory serves.
If this link fails, just search Miesha Tate vs. Holly Holms.
Point of interest is what happens in Round 3, once only 2 minutes five seconds are left in the match ...