Top 5 fighters who went down a weight class and excelled  

#4 Joseph Benavidez

Joseph Benavidez is one of the sport's all time best Bantamweight and Flyweight fighters

The perennial top-contender at the Flyweight division and a veteran of the sport, Joseph Benavidez began his MMA journey way back in the year 2006 fighting in smaller local promotions before eventually signing with the WEC in the year 2008. Benavidez began his career as a Bantamweight fighter and spent his WEC days competing at Bantamweight where he fought elite fighters such as Miguel Torres and WEC Champion Dominick Cruz twice for the WEC belt, but ended up unsuccessful both the times.

On being signed by the UFC, Benavidez continued to compete at 135 lbs and was always a top contender in the Bantamweight division. When Dana White and the UFC announced the inclusion of the Flyweight division, Joseph Benavidez was amongst the first few fighters to make the shift down to 125 lbs and competed at the inaugural Flyweight tournament final against Demitrious Johnson for the newly formed Flyweight title. Benavidez lost to "Mighty Mouse" Demitrious Johnson who then went on the defend his Flyweight belt for a record 11 times before finally losing it to Henry Cejudo.

Benavidez continued to be one of the top contenders at Flyweight and has defeated the elite of the division, including the current champion, Henry Cejudo. He could never really find his home at Bantamweight but has emerged as one of the all-time best fighters to compete at Flyweight division.

#3 Frankie Edgar

Former Lightweight champion Frankie Edgar is a force to be reckoned with at Featherweight

The former UFC Lightweight Champion and a future Hall-of Famer, Frankie "The Answer" Edgar began his UFC career competing at the Lightweight division where he quickly rose through the ranks and challenged the legend BJ Penn at UFC 112. Edgar entered the bout as a huge underdog but to the shock of the world, ended up beating BJ Penn via decision to win the UFC Lightweight title. Edgar went on to defend his title against BJ Penn at UFC 118 and Gray Maynard at UFC 125, a closely fought fight which ended in a draw and UFC 136 where he knocked Maynard out to cement himself as the Champion. Edgar then lost his title to Benson Henderson at UFC 144 and a subsequent rematch as well at UFC 150.

In an attempt to resurrect his career, Frankie Edgar dropped down to Featherweight and in his 1st fight at 145 lbs, challenged the great Jose Aldo for the title. Edgar was defeated by Aldo in a closely fought fight, but this fight marked the beginning of his journey at Featherweight. Ever since his shift to Featherweight, back in 2013, Edgar has fought and defeated the very best in the division and has also challenged for the title 3 times, twice against Jose Aldo and once against Max Holloway, however falling short of glory each time.

Even though he is yet to win a title at Featherweight, Frankie Edgar has been extremely successful in his new division and has established himself as a perennial top-contender at 145 lbs.