#4. Raquel Pennington, UFC 224
In the main event of UFC 224, Raquel Pennington challenged Amanda Nunes for the Brazilian great's bantamweight championship. Before the bout, and indeed the event itself, much was made about UFC 224 being the first UFC fight card to be headlined by two openly gay fighters.
Unfortunately, after the bout, the milestone was all but forgotten due to the proceedings inside the octagon.
Amanda Nunes is the most powerful puncher in women's MMA, able to freeze her foes with only a handful of strikes due to the lack of experience most fighters across all divisions have with facing fighters with such crippling knockout power.
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Nevertheless, Pennington put forth a spirited effort in her bid to dethrone 'The Lioness'. Though try as she might, capturing UFC gold was not in Pennington's realm of possibility that night.
Nunes brutalized her as Pennington became more gun-shy, her self-belief chipped away by every Nunes punch. Between the 4th and 5th rounds, 'Rocky' quit on her stool.
Demoralized and battered, she told her coaches she was done, imploring them to stop the bout. However, in a move that left the MMA world disgusted, Pennington's corner refused to heed their fighter's request.
Instead, they implored her to change her mindset before sending her out for the 5th round in a bout she'd been dominated in from the start. Within two minutes, Pennington was on the wrong end of a TKO, becoming one of the few fighters to quit on the stool but be forced to continue fighting all the same.
#3. Chris Leben, UFC 168
At UFC 168, former middleweight champion Anderson Silva sought to recapture his title from Chris Weidman in their hotly anticipated rematch. On the Brazilian's undercard, a fighter who fans and MMA media members alike once regarded as Silva's successor locked horns with one of the former champion's past opponents: Chris Leben.
Leben's opponent was Uriah Hall, a flashy and explosive striker who many, at the time, believed possessed the tools necessary to one day capture UFC gold. Chris Leben, by contrast, was on a 3-fight skid and was hoping to snap the longest losing streak of his career.
Yet, when he and Uriah Hall clashed, the disparity between the two fighters was evident.
Hall was The Ultimate Fighter finalist's superior in every sense. He was too fast for 'The Crippler' and his footwork dumbfounded a foe without the tools to cut off his opponent's angles of escape.
As Leben lunged forward, Hall pivoted off the center-line at an angle that positioned him on his opponent's open side. From there, 'Prime Time' cracked his foe with a counter-right straight, flooring him at the buzzer.
Leben, known throughout his career for his toughness, did not rise from his stool for the 2nd round. The MMA world watched in shock as 'The Crippler' quit in what was ultimately his last MMA bout, telling his coaches between rounds that he was done with the sport.
#2. Max Rohskopf, UFC on ESPN 11
One of the more recent cases of a fighter quitting during a bout came at UFC on ESPN 11. At the time, Max Rohskopf was an undefeated fighter boasting a record of five wins and no losses.
In what was his UFC debut, the 27-year-old was trailed by a considerable amount of hype. He'd won all five of his bouts by submission, with only one of his foes escaping the 1st round.
The UFC scheduled him for a fight with Austin Hubbard, whose own record at the time featured 11 wins and four losses. Hubbard, however, was a former champion across various MMA promotions ranging from CAMMA and the SCL to Hoosier FC and the LFA.
Worse still, Rohskopf had accepted the bout with only 10 days to prepare, rendering him as ill-equipped as he could have been for his UFC debut.
Rohskopf opened the undercard against his more experienced foe, and as the rounds progressed, it became clear that the young lightweight prospect was either overmatched or underprepared, perhaps both.
By the end of the 2nd round, it was clear to all spectators that Rohskopf had nothing more to give. As he returned to his corner, the lightweight prospect repeatedly told his corner to call off the bout and that he didn't have the will to continue.
Against Rohskopf's wishes, his coaches implored him to continue. However, when the UFC debutant never stood off his stool, referee Mark Smith called for a timeout to assess the fighter's condition.
After being asked if he wanted to resume the fight, Rohskopf refused and the bout was called off. In the fight's aftermath, the MMA world was in uproar, with even the NAC announcing its intentions to investigate the conduct of Rohskopf's corner.
#1. BJ Penn, UFC 94
While a glance at his 32-14 record might imply otherwise, BJ Penn is one of the greatest mixed martial artists of all time. A former UFC lightweight champion who fought too far past his prime, Penn was renowned for his crisp boxing, slick Brazilian Jiu-Jitsu skillset, and daring warrior spirit.
The fearlessness with which 'The Prodigy' navigated his MMA career was such that he even faced future light heavyweight champion Lyoto Machida in an openweight contest.
At UFC 94, however, he was scheduled to clash with another world champion, Georges St-Pierre. It was not the first time that the Hawaiian and the Canadian legends had met inside the octagon.
Both fighters fought to a split-decision win in favor of St-Pierre at UFC 58 years prior to their highly anticipated rematch. With three years between their 1st and 2nd outings, both fighters had changed and evolved.
In the lead-up to their rematch, 'The Prodigy' expressed his willingness to fight to the death before claiming that he'd try to kill his foe inside the octagon.
Furthermore, Penn punctuated his statement by explicitly stating that he was not joking. Undeterred, GSP remained confident, exclaiming that even the best version of BJ Penn would not be good enough to defeat him.
When the two finally fought, the Canadian had the chance to prove his claims. What ensued was four rounds of domination as St-Pierre secured multiple takedowns and battered his foe.
As Penn returned to his corner, he contradicted his previous claims of fighting to the death by imploring his brother to call off the bout. The Hawaiian's request was honored, and GSP was declared the winner via TKO.