Dillashaw (12-2) successfully defended his UFC bantamweight title for the second time Saturday night, dominating Barao en route to a fourth-round TKO finish to headline UFC Fight Night at the United Center.
Dillashaw, 29, took the belt from Barao (33-3) in a TKO victory in May 2014. Dillashaw entered the first fight as a more than 7-to-1 betting underdog. The UFC booked a rematch immediately after Dillashaw's stunning win, but it fell through when Barao fainted the day before the fight attempting to make weight.
The long-awaited rematch looked similar to the first. Dillashaw beat Barao to the punch all night and confused him with constant movement. According to Fightmetric, Dillashaw landed 157 total strikes compared with 77 for Barao.
"He came out a little more aggressive in the beginning and tested my will," Dillashaw said. "I trained hard."
The official time of the finish was the 35-second mark of the fourth. The first fight ended at 2:26 of the fifth.
After hurting Barao with a left hand late in the third round, Dillashaw pounced on him at the start of the fourth. Barao fell back against the fence and briefly went limp twice because of punches, but he somehow managed to stay on his feet and threw punches back.
Barao initially protested the stoppage, but it seemingly was an easy decision to step in for referee Herb Dean.
UFC president Dana White was impressed with both fighters.
"I had some questions about Renan Barao coming into this fight. I didn't think he looked great in his last fight," White said, referring to Barao's third-round submission victory over Mitch Gagnon on Dec. 20. "But he looked great tonight. So did T.J. The kid was putting together combinations. He stood in the pocket and didn't use as much movement as he did the last time. He stayed in the pocket and ended up getting the better of him."
Fighting out of Nova Uniao in Rio de Janeiro, Barao attempted to wrestle more than he did in the first meeting but did not have much success. Early in first round, he landed several good knees to Dillashaw's body from the clinch and then dropped levels for a takedown. He continued to drive into Dillashaw periodically throughout but converted only one takedown, in the second round, which Dillashaw bounced up from instantly.
Dillashaw landed virtually everything he threw. He switched stances constantly, landing right uppercuts, straight lefts, head kicks and jabs from every angle. When Barao did catch him with clean punches -- including a pair of hard right hands in the first round, an overhand right in the second -- Dillashaw made it a point to laugh back at him.
Barao, who cut a substantial amount of weight to make 135 pounds, appeared tired by the third round. His punches slowed, and he started to shoot more desperately for takedowns. Dillashaw stuffed each of them, usually landing a left hook or short right hand afterward. Barao turtled up after one failed shot, providing Dillashaw an opportunity to jump to his side and land a knee to the body.
Former UFC champion Dominick Cruz (20-1), who was stripped of the title last year because of inactivity, is expected to challenge Dillashaw next. Cruz is currently recovering from his third ACL surgery, which took place in January. Dillashaw has already expressed an interest in fighting Cruz, who is a longtime rival of Urijah Faber, Dillashaw's teammate.
"That's the biggest fight," Dillashaw said. "That's what's going to make my name the biggest, is fighting Cruz at this weight class. He's a very elusive, high-pace fighter as well. I just don't think he has the power behind his punches. I don't think he has that devastating threat he can impose on someone. I definitely see myself winning that fight."
Attendance for Saturday's card was 11,663 for a live gate of $1.2 million.