Before Max Holloway was the BMF champ, he fought Conor McGregor on the prelims

This article is part of a new series by FanSided MMA honoring milestones and memories from the past. Watch for a new flashback feature every Thursday.

Conor McGregor is without a doubt the biggest star in the history of mixed martial arts. However, the announcement of his return to the Octagon after an almost three-year layoff was overshadowed by one of the greatest knockouts the sport has ever seen.

Max Holloway putting Justin Gaethje to sleep with an overhand right after deciding to play human Rock 'Em Sock 'Em Robots in the final seconds of a fight he was dominating cemented his status as the BMF. That knockout has propelled Holloway to a new level of stardom with a clip of the knockout receiving over 3 million likes on Instagram, but long before they were the sport's biggest star and the BMF, McGregor and Holloway faced off on the preliminary card of UFC Boston.

It was Aug. 17, 2013, and the Octagon was touching down in Boston, Massachusetts for just the second time in the promotion's history. Buried on the prelims of a card sporting names like Chael Sonnen, Mauricio "Shogun" Rua, Alistair Overeem, and Urijah Faber, was a matchup between a brash 25-year-old with a devastating left hand and a 21-year-old who embodied the Hawaiian fighting spirit.

McGregor had come to the UFC with a ton of hype after winning both the featherweight and lightweight championships in Cage Warriors, the premier British MMA organization. His 67 second knockout of Marcus Brimage in his promotional debut only furthered the intrigue surrounding the young McGregor.

Holloway, on the other hand, had debuted in the UFC a year and a half earlier as a late replacement against future multiple time title challenger, Dustin Poirier. Holloway had gone 3-2 during his time in the UFC and was coming off of a decision loss to Dennis Bermudez.

The difference in where these two men were at in their respective careers was evident from the walkouts. Holloway walked out to little fanfare, while the reaction McGregor received was as if he was the main attraction on the card.

Max Holloway vs. Conor McGregor flashback recap

The McGregor that was in the Octagon that night is far from the superstar we know today. Sporting a single tattoo and fighting at 145 pounds, his style was built on outstanding footwork and a very kick heavy attack, punctuated by a crushing straight left hand. His confidence was there, but his demeanor was that of a young fighter who was hungry to reach the top of the sport.

Holloway was further from his prime at that point in his career. He showed glimpses of the fighter he was to become with spurts of volume heavy boxing and his trademark toughness, but seemed unable to find his rhythm.

The first round of the fight played out with McGregor putting his masterful footwork on full display, constantly cutting Holloway off and attacking with a variety of kicks. The disparity in skill was evident as Holloway was never able to put McGregor in any kind of danger.

The second round started in similar fashion with McGregor controlling the Octagon until he caught a Holloway kick and dumped him on the ground. While attempting to pass Holloway's half guard, McGregor tore his ACL.

With his movement severely compromised, McGregor was forced to rely on a grappling game that up until that point had been an unknown. Displaying the resolve and adaptability that all champions need, McGregor was able to ride out the third round on the ground and earn the unanimous decision victory.

As can often be the case in combat sports, the timing of this fight seems a bit unfortunate. McGregor was much closer to the finished championship product he would become, while Holloway was just starting to realize his potential.

Within two years, McGregor would be the sports biggest star, leading a worldwide promotional tour for his showdown with José Aldo. The 13 second knockout of Aldo that followed launched McGregor to heights of superstardom that the sport had never seen and may never see again.

Holloway would use the loss to McGregor as a learning experience, going on a five and a half year, 12 fight win streak that included wins over Charles Oliveira, Anthony Pettis, and the aforementioned Aldo. With his name all over the UFC record book, Holloway is now widely considered one of the greatest fighters of all time.

One of the promotional videos for UFC 300 showed hypothetical matchups between some of the sport's biggest stars. With the announcement of McGregor's return and Holloway delivering one of the greatest knockouts of all time, one can't help but wonder what the fight between these two men would have looked like had they both been in their prime.