Henderson and Edgar battled almost to a standstill in their lightweight title fight in the main event at the Pepsi Center.
Henderson pulled out a split decision, winning 48-47 on two cards and losing 49-46 on the third to retain the title he won from Edgar at UFC 144 in Japan.
Edgar was elusive and difficult for Henderson to catch. Henderson, who had an 89-62 edge in strikes landed, was scoring well with kicks early in the fight. But as the bout wore on, Edgar was more in control.
The decision is sure to spark plenty of debate. It drew the ire of the crowd on Saturday, and Edgar won 49-46 on the Yahoo! Sports card.
Henderson celebrated when the fight end, but admitted he wasn't sure when it was announced that he'd kept his belt.
"Of course, you always have concern when it goes to the judges," Henderson said.
His biggest concern was in the second after Edgar caught him in a choke. But Henderson has been the most difficult man to submit in the UFC and he kept that reputation intact, holding on before finding a way to get out of it.
Edgar wasn't able to land the big shots that he had been in other fights, but he also didn't take nearly as much damage as he had in others. He had a minor bloody nose and a nick around his right eye, but otherwise was clean.
"I thought I had it," Edgar said, shrugging his shoulders.
In the end, it was probably Henderson's volume of kicks that swayed the judges. Henderson will defend his belt against Nate Diaz next, according to UFC president Dana White.
Donald Cerrone and Melvin Guillard are friends and long-time training partners, but they sure didn't fight like it. Just seconds into the fight, Guillard dropped Cerrone with a vicious counter left.
But about a minute later, Cerrone reversed things and scored one a brutal knockout of Guillard. Cerrone landed a kick to the head that wobbled Guillard and stopped him in his tracks. Cerrone then landed a crushing right hook to the chin that put Guillard down and out.
It was a devastating finish to a fight that was expected to be one of the year's fiercest. Both are known for their high-energy style and finishing ability, and the fight lived up to the hype in just the 76 seconds it lasted.
Jake Shields' return to middleweight was not exactly a big hit. Shields took Herman down and would hold him on the ground for long periods as he worked for better position. The crowd hated it, though, and booed loudly throughout.
And so, though Shields won a unanimous decision, he hardly helped himself. Even UFC president Dana White blasted the fight for its lack of action on his Twitter account, calling it terrible.
Shields, though, was in control most of the way and had little trouble neutralizing Herman's offense.
Ex-middleweight title contender Yushin Okami snapped a two-fight losing streak, using his wrestling to control Buddy Roberts and pound out a second-round stoppage victory.
Okami took Roberts down late in the first and took his back. He nearly finished the bout then, pummeling Roberts with shots. Dean was close to jumping in, but the bell sounded to save Roberts.
But the second round picked up where the first left off. Roberts was taken down and Okami patiently maneuvered into position. He got into mount, but Roberts then rolled onto his stomach. At that point, Okami used the same tactic he did in the first. He landed 15-20 unanswered blows before it was stopped at 3:05.
"With this, I feel like I'm on the path back," Okami said of snapping his losing streak. "I came to Denver early so that I would be in the best condition possible for this fight. I was able to use my ground and pound, which is my best weapon."
In the pay-per-view opener, 20-year-old striker Max Holloway finished Justin Lawrence at 4:49 of the second round with a pair of perfectly placed body shots.
Holloway was patient despite the fact he was having difficulty getting the distance correct early in the fight. But late in the second, he opened with a jab that backed Lawrence to the cage. He then ripped a pair of shots to the body that sent Lawrence slumping to the floor, covering up.
Holloway jumped on top of him and landed a series of shots before referee Josh Rosenthal stopped it.
"That was my best fight to date by far and I was able to go in there and get the finish," Holloway said. "I don't have too many finishes on my record, so that's always a bonus. We're both strong strikers and a lot of times when two strikers get in there, it can turn into a wrestling match. I'm glad Justin went in there and banged with me and I'm even happier that I came out on top. I saw the first knee and the body shot and he went down so I knew he didn't want to fight anymore. I jumped in there and got the finish as quickly as I could."