BOSTON » B.J. Penn entered the Octagon and walked over to the champion’s corner before being told he was on the wrong side.

It might be the last time he’s ever in that position.

Penn was outworked, outhustled and flat-out beaten for five rounds in a unanimous decision loss to Frankie Edgar in the main event of UFC 118 last night before 15,575 at the TD Garden.

Unlike the first fight, when the decision was disputed, this one was a no-brainer. All three judges scored all five rounds for Edgar (13-1), who beat Penn (15-7-1) in every aspect of the bout.

"I definitely wanted to make it decisive so there was no questions," Edgar said. "Nobody can say anything now. It went my way."

In an arena known for the Boston Celtics’ championship banners that hang from the rafters, Penn’s championship status in mixed martial arts has come to an end for a while.

How long remains to be seen, but it’s clear for the first time since he returned to the UFC that he’s not the best lightweight in the world.

Edgar put on another masterful display standing, moving in and out on Penn and repeatedly beating him to the punch.

The most surprising part of the fight came when Penn took down Edgar twice, but couldn’t do any considerable damage. Edgar got to his feet quickly both times.

"Frankie looked like an absolute mixed martial artist," UFC president Dana White said. "Picking B.J. Penn up and slamming him many times, B.J. almost had him in the mount position and he got off the mount.

"I had Frankie Edgar winning every round."

Edgar started the fight strong, taking down Penn, who is known for his takedown defense. Penn’s guard made it hard for Edgar to inflict much damage, but there was nothing else Penn could do.

In each of the last two rounds, Penn was able to take Edgar down, something he didn’t do in the first fight. However, Edgar was too strong to hold on the ground. In the fifth round, he even managed to sweep Penn, a black belt in jiu-jitsu, and take top position.

"I felt like I was winning the fight, but I didn’t want to let up," Edgar said. "I felt (Penn) fading a little bit, but B.J. is still a dangerous fighter, fading or not."

The victory establishes Edgar as a credible champion and the new face of the UFC lightweight division. He will get a chance to avenge his only professional loss when he defends the belt next against Gray Maynard.

Maynard earned the title shot with a unanimous decision over Kenny Florian earlier last night.

While Edgar’s future is settled, the opposite holds true for Penn, who turns 32 later this year.

He’s by no means old, but he looked nothing like the guy who ripped through Diego Sanchez and Florian last year.

Nicknamed "The Prodigy" for his undeniable skill, Penn was turned into an average fighter by the champion.

His stand up was no match for Edgar. His ground game imposed no problems and once again he fatigued toward the later rounds.

"I’ve really got to go back and think about things," Penn told UFC commentator Joe Rogan in the cage after the fight.

Penn didn’t attend the postfight press conference, and White speculated he may have had to go to the hospital, but that wasn’t confirmed.

White was unsure about Penn’s next fight in the UFC.

"That’s an interesting question," he said. "I don’t know."