1. Ronda Rousey v Liz Carmouche
Ronda Rousey was the champion in Strikeforce and rolling through women, so the UFC decided to take a chance on her. They made her the inaugural bantamweight champion and threw her in at UFC 157 against Liz Carmouche. There was massive pressure on Rousey because Dana White had previously said that women would never fight in the UFC.
The event was built around Rousey and was a massive turning point in the sport. Carmouche put her in massive danger at the start of the fight, but would eventually typically armbar her way to victory. She still has the longest title defence streak out of any female UFC champion. The sport may have evolved since her day, but the significance of this fight puts it in the first place.
