LAS VEGAS – After getting stitched up by a doctor for cuts opened by Frankie Edgar, ex-champ B.J. Penn ended any speculation about his next move.

Pounded out by Edgar (17-4-1 MMA, 11-4-1 UFC) in the third round a headliner at The Ultimate Fighter 19 Finale, which capped a banner event for the UFC with International Fight Week, Penn (16-10-2 MMA, 12-9-2 UFC) made it clear he will fight no more.

“This is the end,” he said at the event’s post-fight press conference at Las Vegas’ Mandalay Bay Events Center. “I’m thinking to myself, ‘Why did you step back into the octagon after the beating that Rory MacDonald gave you?’

“And the reason is I really needed to find out. If I didn’t make this night happen for myself, I would have always wondered and went back and forth and begged Dana to let me back in. I guess I needed some closure.”

For Penn, the realization came in the middle of his fight with Edgar as things started to go badly wrong, which was almost from the outset of a possible five-rounder. Edgar, who beat Penn in a pair of 2010 bouts to seize and hold the UFC lightweight belt, was faster, more accurate, and more devastating at every turn.

Moments before referee Herb Dean saw enough and waved off the bout, Penn took a series of elbows that opened him up and necessitated a visit afterward to the doctor.

“When the blood started going in my eyes and everything and the fight started getting real tough, I realized it takes a high, high energy level to compete with the top people in the world,” he said. “You can have every technique figured out, you can have this and that and all your theories ready to go, and at the end of the line is you need a high energy to compete against these guys.

“They’re very hungry, they want to be the best. I can sit here a thousand times and say the sport passed me by, but there’s just such quality people in the UFC at the moment.

“You look at somebody like Frankie Edgar, and you think, ‘That little guy,’ but these guys, they want it,” he added later. “And even if you’re sitting there and you think you’ve got something figured out, or you’re going to surprise somebody with (something), first thing you’ve got to do is have more heart than these guys. That’s what all these people have a lot more (of). You can’t see that looking at them; you can only see it by feeling it.”

Penn joked with a reporter that his best moment in the fight was “walking out, probably.”

A beating at the hands of Rory MacDonald at the end of 2012 prompted Penn to walk away from the sport. But it also caused him to question whether the performance was the result of a bad night on the job or a signal that it was time to hang up his gloves.

He convinced UFC President Dana White to give him another shot and signed on to coach “The Ultimate Fighter 19” opposite Edgar, who didn’t hesitate to give Penn a third fight despite two previous victories over the fighter.

“The biggest regret would be if I didn’t get in the ring tonight,” Penn said. “I’d always kick myself in the butt and complain to (UFC President)Dana (White) and complain to everybody, ‘Man, I could have done it again.’ Now I know for sure that I can’t.”

Penn retires with a 16-10-2 record and leaves a legacy as a fighter who never shied away from impossible goals, among them to win titles in three weight divisions. As he leaves it, “The Prodigy” remains one of only two UFC fighters in history to own belts in two divisions, at lightweight and welterweight.

He is a shoo-in for the UFC Hall of Fame. UFC President Dana White lauded the fighter as someone who helped build the UFC.

White and Penn once wound up in court in 2004 when the fighter decided to pursue bigger purses overseas after taking the promotion’s welterweight title from then-champ Matt Hughes, but the two moved past their rift and shared a positive, if challenging, relationship in Penn’s latter career.

Some of Penn’s greatest heights and lows came as the result of rivalries with a trio of UFC stars: Hughes, Georges St-Pierre and Frankie Edgar.

“My best moment in the UFC, I guess now that I look back, it’s the two belts in the two weight classes,” Penn said. “I really wanted to see if I could make it three, but you’re talking about the best guys in the world.

“I think that’s what made my career something to watch is that I did have these rivals throughout the years. Everybody always talked about Roy Jones at the beginning of his career. He never had anybody to fight against, and that’s what makes a career great. I was actually blessed to have these rivalries with these three people.”

Penn struggled to answer the question of how he will be remembered in the sport beyond highlight reels that play at UFC events. He did, however, say he will continue to be a part of the sport as a partner at a UFC-branded gym in his native Hawaii.

Stepping away from the sport completely, he said, would be difficult.

Penn came back to see whether he could feel satisfied with a victory over Edgar or whether he still had the hunger to be a champion once again. He got his answer, but one thing never changed over the years: Fans resonated with him in ways that he didn’t always understand and left him filled with gratitude.

“It would be the strangest thing,” Penn said. “I’d lose a fight, and I’d go walk down the road, and I couldn’t walk down the road. I’d say I’m getting more famous every time I’d lose a fight.

“People could connect with me; they felt that I was just a normal human being. In the off-season, I’m overweight, and I’m just trying my best, just like anybody else. I think the appeal was that here he is, he’s just a normal guy like us, and he’s giving it his all.”

For complete coverage of The Ultimate Fighter 19 Finale, stay tuned to the UFC Events section of the site.