If you wanted to draw a line in the past to separate the modern era of the UFC from its primordial early phase, you could do a lot worse than to plant that barrier on April 9, 2005.

That’s the night the first season of “The Ultimate Fighter” officially wrapped up with a finale event at Cox Pavilion in Las Vegas. More importantly, it’s the night Forrest Griffin and Stephan Bonnar went three wild rounds for the honor of being the light heavyweight winner of that first TUF season, and in so doing maybe saved the UFC or even all of MMA.

It’s hard to be sure now. The further we get from the actual event, the more the myth threatens to overtake the reality. The story gets told and retold until it finally coalesces into an agreed-upon version that may or may not be grounded in pure fact.

It’s not just another fight at that point; it’s a vital piece of MMA lore.

It started with the reality show. You take 16 fighters, middleweights and light heavyweights, pair them with a couple of coaches who are going back and forth for the title, throw in a singer no one has ever heard of and add a bunch of poorly thought-out challenges, and boom, the sport should be mainstream by the summer.

As UFC executives would later frame it, this was a final Hail Mary, one last shot at getting on TV and getting noticed. It worked, for a price, but it couldn’t work this way indefinitely. The UFC put the right pieces in place, but it needed everything to go right for the gamble to pay off. You can put some fights on cable TV, but you can’t guarantee they’ll be good fights.

And, man, some good fights would really be nice right about now, when you’re still trying to capture the attention of the average sports fan during this fleeting moment in which you have it.

That was the UFC’s situation headed into that first TUF Finale on that April day in Vegas. The main card consisted of only three fights, giving almost no time for momentum to build. It was nominally headlined by a light heavyweight bout between rising contender Rich Franklin and aging star Ken Shamrock, who was past his prime even then. But first came the middleweight finale, where Diego Sanchez absolutely mauled an undersized Kenny Florian to become the first TUF winner in UFC history.

Forrest Griffin and Stephan Bonnar were inducted into the UFC Hall of Fame together in 2013.

Neither of these were particularly great fights. Mostly one-sided and looking more like showcases than competitions, they both ended in the first round, providing a combined total of just over five minutes worth of action. It was the fight sandwiched in between them that really worked the magic.

Griffin joined the cast of TUF 1 after requesting a leave of absence from his job as a sheriff’s deputy in Georgia, where he promised his superiors that he would conduct himself “in a manner that will not embarrass you or this department.” Aside from occasional stir-crazy moments while cloistered in the fighter house, he mostly kept that promise – or at least did far better than most of his peers.

Bonnar was the jovial Carlson Gracie product who had submitted Mike Swick to punch his ticket to the finale, despite almost getting kicked off the show for sneaking out of the house to buy booze at one point during the filming.

If you hadn’t watched every episode of the reality show, you likely had no idea who either of them were. Even if you did watch the show, you had only a limited idea of what to expect. What really sold these fights were the purported stakes – two men, one “six-figure” UFC contract.

That was the context that made what came next seem extra special. After the introductions, which consisted of Bruce Buffer referring to Stephan Bonnar as “Stephen,” the fighters quickly waded into an all out slugfest that would carry on throughout the three-round bout.

Was it a pretty fight? It was not. But what it lacked in technical grace it more than made up for in intensity. Clad in plain black gloves without even a UFC logo, the fighters spent the first round taking turns on offense, with both men landing wild strikes that brought cheers from the crowd and reflexive utterances of surprise and delight from the commentators.

“What a war between these two guys,” UFC commentator Joe Rogan remarked at one point. And the first round wasn’t even halfway over yet.

Stephan Bonnar and Forrest Griffin during the TUF 1 Finale.

Soon the battle took on its own rhythm. One man wading in with looping punches while the other hung back, waiting to counter. Then the messy struggle in close, knees and short uppercuts from the clinch, each man searching for the other’s breaking point.

In the second is where it really got messy, thanks to a cut around Griffin’s eye. Soon the blood was flowing and the pace only seemed to increase, as if just the sight of the blood jacked up both men’s intensity.

But as the fighters tired at a more or less identical rate, that’s when the fight began to feel more desperate, more urgent. Each man seemed like he could barely stand, or like he might be one more good shot away from being planted on the mat for good. And yet each time that shot came, he weathered it, absorbed it, and fired back with one of his own. It didn’t seem like it could possibly last, but somehow also felt like it might never end.

It was this quality, more than any other, that most effectively served the UFC’s purposes at the time. As UFC and Spike TV executives would later recall, it was a battle made for TV ratings, as people seemed to be reaching out to friends mid-fight, telling them to turn on their TVs and look at this crazy, bloody mess.

By the end, picking a winner was almost like flipping a coin. Buffer got on the mic and informed fans that they had just witnessed “three rounds of the greatest action seen inside the octagon in the history of the UFC.” Already the legend was building.

The judges went unanimously for Griffin, who could only smile in mild surprise as he raised his arms. Bonnar sunk slowly to his knees and then collapsed onto his face, an act that seemed like part disappointment and part total exhaustion. It was Griffin who pulled him back to his feet and embraced him, all while Buffer asked the crowd to give a big hand to “Stephen Bonnar.”

Soon after, a svelte UFC President Dana White appeared, announcing the host of prizes that Griffin would receive in addition to his UFC contract (including a Scion, a dirt bike and a watch). He quickly added that he had conferred with the Fertittas and decided that there was no loser to this fight, so Bonnar would get a contract as well.

The announcement brought the crowd to its feet, with even Buffer cheering in the background. This is how completely people bought into the idea back then that only one TUF finalist would even make it into the UFC.

It was the success of this fight and this event, White would later claim, that made Spike commit to more seasons of TUF, more UFC, until soon it was a programming staple. This was the UFC’s foothold on TV, the basis for building its core audience and directing them to the pay-per-views that would feed the company coffers in the years to come.

Would it have happened without these two unknown light heavyweights beating each other bloody one night in April? Maybe. Maybe not. Or maybe it just would have taken longer to get to the same place.

But this was the right fight at the right time, a perfect indication of where MMA was and what it could be. A wild and crazy mess, perhaps, but a thrilling one at times. One you couldn’t look away from. One that made you want to call a friend, tell them to get to a TV, and hurry, because this could end at any moment.

“Today in MMA History” is an MMAjunkie series created in association with MMA History Today, the social media outlet dedicated to reliving “a daily journey through our sport’s history.”