5 best UFC fighters under the age of 25

#2. Casey O'Neill - UFC women's flyweight - 24

Casey O’Neill holds a record of 9-0

Just two spots above Maycee Barber in the UFC women's flyweight rankings sits Casey O'Neill at no. 12. While O'Neill might not have quite as much octagon experience as the former, her performances thus far have been exceptional. So far, she is a perfect 4-0 since joining the promotion.

O'Neill managed to secure stoppage victories in each of her first three fights inside the octagon. This included a bonus-winning performance against Antonina Shevchenko, sister of the current champion Valentina Shevchenko. However, her most recent bout against Roxanne Modafferi finally saw her fight to a decision.

With O'Neill now climbing the rankings and showing no signs of slowing down anytime soon, who knows how far she may go. After her last bout, she indicated that she would be taking a little time to avoid burning out. Given time is still very much on her side, this could well prove to be a wise decision.

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#1. Song Yadong - UFC bantamweight - 24

Song Yadong holds a record of 19-5-1 the (1 NC)

Fresh off his win this weekend, Song Yadong tops this list due to the wealth of impressive performances he has racked up at such a young age. He first debuted with the promotion at just 19 and staggeringly made his professional debut when he was just 15.

He won his promotional debut and has put together a very impressive 8-1-1 record inside the octagon to-date. He's competed at both bantamweight and featherweight and has earned some impressive victories along the way. Thus far, the prospect has beaten the likes of Marlon Vera and recently, Marlon Moraes.

Song Yadong is now on a three-fight winning streak and recently broke into the bantamweight top 10 at no. 9. He is now set up for a number of big-time fights given how deep the bantamweight division is and will surely face plenty of big stars given he's still just 24.