Poirier (22-5) picked up a submission win when Pettis (20-7) tapped out at 2:08 of the third round. The fight headlined UFC Fight Night at Ted Constant Convocation Center in Norfolk, Virginia.
Pettis appeared to tap due to an injury, as he wrenched his body awkwardly in an effort to escape Poirier's full mount. Poirier had dominated the fight to that point, and he wasted no time calling out his next opponent.
"Everybody points the finger, says I slip up in big fights -- that's two champions in a row. What's up?" Poirier said.
"I'm not gonna ask for a fight. I'm gonna tell you the fight," said Poirier, saying he wants the winner of the Dec. 2 fight between Justin Gaethje and Eddie Alvarez. "Then I'll fight for the title. There, I laid it out for you guys."
Poirier, who fights out of American Top Team in South Florida, is 6-1 since moving up from featherweight. He arguably would be 7-1, but his previous fight, against former lightweight champion Alvarez at UFC 211, ended in a controversial no contest when Alvarez landed illegal knees.
There was no controversy Saturday, despite the unusual nature of Pettis' tap. Poirier outlanded Pettis in total strikes 71-46, according to Fightmetric, and opened a deep cut over Pettis' left eye with an elbow.
The cut was so bad that the Virginia commission paused the bout in the second round to inspect it. Pettis, of Milwaukee, fought through the injury and threatened Poirier with several triangle submissions off his back, but he struggled to match Poirier's offense.
Poirier nearly finished Pettis with strikes at the end of the opening round. He hurt Pettis with a right hand to the temple and a long flurry up against the fence. Pettis did respond with a stinging uppercut, but Poirier took it and continued to unload shots.
"I knew he was hurt," Poirier said of Pettis. "He was bleeding a lot. I felt his power go. I felt he wasn't giving it his all anymore. You know the point in a fight where the guy doesn't want to be in there anymore, and I do that to a lot of these guys. I'm a nasty dude."
Poirier, 28, is in the midst of the best run of his career. He was disappointed with the UFC when the promotion didn't book an immediate rematch with Alvarez after UFC 211, but he is in a good spot now to call his shots.
It was another tough night for Pettis, who is now just 2-5 in his past seven. He has been finished in two of his past three, including a third-round TKO loss to current featherweight champion Max Holloway.
Brown lands show-stopping elbow on Sanchez
After originally declaring Saturday his retirement fight, Brown, 36, walked back the claim during fight week. If this does prove to be his final fight, what a way to go out.
After catching a front kick, Brown sized up and landed a perfect right elbow strike that folded Sanchez up on the canvas. It was the 13th knockout of Brown's career.
"We'll see what happens," Brown said of his future. "I'll talk about it with my family over the holidays. As of now, I had to keep my focus on Diego. If you don't put your sole focus on him, he'll whup your ass."
The finish came after Brown was visibly hurt by a Sanchez liver kick. He also took a heavy right hand over the head in the clinch but recovered quickly.
For Sanchez, who moved back up to welterweight from lightweight for Saturday's bout, it was his fifth loss by knockout.
Assuncao posts highlight KO, calls for Dillashaw trilogy
Bantamweight contender Raphael Assuncao (16-5) improved to 10-1 in his past 11 fights, and did so in highlight-reel fashion.
Assuncao, who fights out of Atlanta, dropped Matthew Lopez with a single right hand at the 1:50 mark of the third round. Lopez (10-2) went out immediately from the shot.
It was only the fourth knockout of Assuncao's career, but it came at a great time. Assuncao, 35, is keen on a trilogy fight with champion TJ Dillashaw. Assuncao and Dillashaw have split two previous meetings.
"Let's go ahead and get moving," Assuncao said. "My only loss was to TJ Dillashaw. That's my only loss at 135 [pounds]. We have to do the trilogy. That's the only thing on my mind.
"I'm not the most talkative guy out there, but I think I earned it."
It took Assuncao most of the first round to find his groove, against a lanky southpaw in Lopez. Once he found it, however, he was devastating. He terrorized Lopez's lead leg with inside kicks, which helped set up the fight-ending punch along the fence.
Northcutt looks outstanding in decision win
Northcutt, 21, completely befuddled Quinones on the feet, outlanding him in total strikes 74-19. All three judges scored it easily for Northcutt, 30-27.
It was Northcutt's first appearance since he committed to training full time with Team Alpha Male in Sacramento. The work clearly paid dividends in this matchup, as he put on a steady, composed fight, which included perfectly timed takedowns late in the first and second rounds.
After dabbling at lightweight and welterweight, Northcutt is set at lightweight for the immediate future and improves to 4-2 overall in the UFC.
Moraes defeats Dodson via split decision, calls for Rivera fight
The final scores looked a little wacky. Two judges scored 30-27 for Moraes, and a third scored it 30-27 for Dodson. ESPN had it 29-28 for Moraes.
Moraes, of Rio de Janeiro, survived a brief knockdown in the opening round and was slightly outlanded in total strikes, but his variety of body kicks, head kicks and right hands created plenty of offense. He also locked in a deep guillotine in the final seconds of the fight.
"Jimmie Rivera, you have no opponent. I'm here," Moraes said. "You talk a lot, knock people out in the gym. I did that, but I don't have to say that. Dec. 30, [UFC matchmaker] Sean Shelby, send me the contract."
A former WSOF champion, Moraes is 1-1 now in the UFC. ESPN.com ranked Dodson and Moraes the Nos. 7 and 8 bantamweights in the world coming in.
Guida knocks out Lauzon in 67 seconds
Guida stunned Lauzon with an overhand right and then floored him with an uppercut. Lauzon tried to recover but was badly hurt. Guida dropped elbows until the referee mercifully stopped it.
It was the fastest finish of Guida's career, and his first knockout since 2008.
After the fight, Guida revealed it was the final bout of his current contract. He implored UFC fans to let the organization know his worth, and said he wishes to finish his career in the Octagon.