Sung landed hard punches, power takedowns and devastating kicks. But it was a D'Arce choke in the fourth that put the highly-rated Poirier out.
Trailing after two rounds were in the books, Poirier bounced back in the third with hard right jabs and powerful lefts that caused swelling around Jung's left eye.
"He had me in trouble at the beginning of the third round," Jung said. "The thought (of losing) was in my head."
Jung appeared to tire heading into the fourth. But a hard right hand sent Poirier (12-2) against the cage. Jung followed with a flying knee to the chin that stunned Poirier, who lost for only the second time as a professional.
With his opponent clearly hurt, Jung took him to the ground where he applied the D'Arce choke, forcing referee Dan Miragliotta to stop it at the 1:07 mark.
The loss is huge for Poirier, who entered the bout on a five-fight win streak and with a No. 3 ranking among featherweights by ESPN.com.
He was hoping to earn a title shot with a victory over Jung. But that opportunity might go to Jung, who improves to 13-3.
Sadollah outmaneuvers Lopez for split decision win
In a welterweight bout between two fighters in need of a win, Amir Sadollah and Jorge Lopez spent much of their three-rounder against the cage.
Lopez initiated most of the grappling in an attempt to get Sadollah to the ground. He failed most of the time and paid a hefty price for his strategic decision -- coming out on the short end of a split decision.
Two judges favored Sadollah 29-28, while the third had it 29-28 for Lopez. ESPN.com scored it for Sadollah 29-28.
Lopez started quickly, landing hard strikes and controlling much of the action during Round 1. But his energy level diminished in the second and third rounds as he looked to take Sadollah to the ground.
Sadollah defended the takedowns and landed several hard strikes as the two maneuvered for position against the cage.
The win allowed Sadollah to rebound from a unanimous decision loss to Duane Ludwig in August 2011. He improves to 7-3.
Lopez (11-3) remains winless in UFC competition at 0-2.
Cerrone outstrikes hard-punching Stephens
Cerrone impressed all three judges with hard punches and kicks that hurt Stephens throughout the bout. Each judge scored the fight 30-27.
ESPN.com also had Cerrone winning 30-27.
Cerrone (18-4) didn't just impress with his striking, he also showed off solid footwork that helped him avoid Stephens' hard punches.
After the win, Cerrone complimented his foe, who absorbed many punches and kicks but never stopped coming forward.
"He came and brought it and did what he said he was going to do," Cerrone said of Stephens.
The loss drops Stephens to 20-8. He has now lost two in a row.
Speedy, hard-kicking Jabouin defeats Hougland
Yves Jabouin landed spinning back kicks and hard right hands en route to a dominating unanimous decision over tough Jeff Hougland.
Two judges scored the fight 30-27, while the third had it 30-26. ESPN.com scored it for Jabouin 30-26.
The speedier Jabouin scored repeatedly with spinning back kicks. One kick landed in Hougland's midsection, sending him to the canvas in the first round.
"Once that back kick lands, not many people can take it," said Jabouin, who improved to 18-7. "He took it like a man."
Jabouin would drop Hougland again in the third and appeared close to finishing the fight with hard punches to the head. But Hougland refused to be put away.
Hougland covered up and briefly gained top position on Jabouin. But Hougland (10-5) couldn't maintain the position and Jabouin delivered more punches.
Pokrajac wins close slugfest over Maldonado
After going toe-to-toe for three rounds with a skilled boxer and eating several hard punches to the body, Igor Pokrajac was awarded a unanimous decision over Fabio Maldonado in their light heavyweight bout.
The judges scored the fight 29-28, 30-27 and 29-28. ESPN.com had it 29-28 for Pokrajac.
The crowd booed loudly when Pokrajac was declared the winner.
Pokrajac extended his win streak to three, while improving to 25-8 overall.
Maldonado falls to 18-5. He has now lost two straight.
Lawlor knocks out MacDonald in first
It was a straight left followed by an overhand right that put MacDonald on rubbery legs. He would fall flat on his face and Lawlor delivered another left for good measure.
Referee Todd McGovern jumped in to stop the action at the 50-second mark.
Lawlor improves to 8-4 and rebounds from a first-round submission loss to Chris Weidman on Nov. 19.
MacDonald now waits to learn his fate in the UFC after losing for the fifth time in his six most recent outings. He has a professional record of 26-16.
Tavares wins foul-filled bout with Yang
All three official judges scored the fight 29-28. ESPN.com also had it 29-28 for Tavares, who improves to 7-2.
The fighters opened the fight aggressively, taking turns exchanging strikes. But an otherwise exciting first round was marred by three pokes to the eye.
Tavares unintentionally poked Yang twice. Yang, also unintentionally, found Tavares' left eye once.
Before the start of the second, Tavares informed a cageside physician that he had blurred vision. But when informed that the fight would be stopped, Tavares said he could see just fine.
The fight was allowed to continue.
Later in Round 2, Tavares would catch Yang with a low kick to the groin. Yang (10-3) took about a minute to recover before informing referee Dan Miragliotta that he could resume fighting.
Grant dominates Prater standing and on the ground
TJ Grant entered his showdown with Carlo Prater struggling to find his rhythm. He found it in this lightweight bout.
Grant controlled Prater both standing and on the ground en route to a lopsided unanimous decision victory.
All three judges scored the fight 30-27. ESPN.com also had Grant winning 30-27.
Grant applied an armbar with seconds remaining in the third round, but the horn sounded before he could complete the submission attempt.
By winning his second fight in a row, Grant improves to 18-5. Prater drops to 30-11-1.
McKenzie survives choke to submit LeVesseur
There is no quit in Cody McKenzie.
For nearly two minutes into his lightweight bout, Marcus LeVesseur seemed to be getting the better of the action.
LeVesseur dropped McKenzie with a hard right uppercut, then punished him with several more hard punches. McKenzie would soon find himself in a choke hold. But he'd escape and apply a rear-naked choke of his own.
McKenzie was able to tighten his grip, forcing LeVesseur to tap at 3:05 of the opening round.
The win helps McKenzie (13-2) snap a two-fight skid. LeVesseur, who was making his UFC debut, falls to 21-6.
Dos Anjos sets up submission with kick
Shalorus tried defending the submission attempt, but dos Anjos never loosened his grip and got the tap at 1:40.
Dos Anjos improved to 16-6. Shalorus (7-3-2) fell to 0-3 inside UFC.
Eduardo's kicks prove too much for Curran
Johnny Eduardo delivered hard Muay Thai kicks to punish the left leg of fellow bantamweight Jeff Curran en route to a unanimous decision.
Each judge, as well as ESPN, scored the fight 29-28 for Eduardo, who earned his first win in UFC. He improved to 26-9.
Curran fell to 35-15-1.
Rivera earns first win in Octagon
Francisco Rivera stalked and landed hard right hands throughout his bantamweight fight with Alex Soto.
Rivera hurt Soto several times in the fight, impressing all three judges who had him winning 30-27. ESPN.com also saw it for Rivera 30-27.
With the victory Rivera improved to 8-2. Soto, who spent much of the bout in retreat, slips to 6-2-1.