Updated

CHICAGO --- There can no longer be any dispute - TJ Dillashaw is the best 135 pound fighter in the world. The 29-year old bantamweight champion successfully defended his title Saturday against the man he took it from a year ago, Renan Baro, winning via fourth round TKO.

The UFC's bantamweight division has gone through several years of near-constant upheaval and uncertainty ever since former champion Dominick Cruz lost his title to injuries. TJ Dillashaw became the second man to succeed Cruz in a short period of time last year when he stopped then-champion Renan Barao, but on Saturday night he solidified his reign with a violent finish in his rematch with the Brazilian.

In their first fight, Barao came out slow and got hurt early. In their UFC on FOX main event, however, Barao bounced on his toes, fired off strikes and mixed in takedown attempts from the start.

"He tested my will," Dillashaw said after his win.

"But, ultimately I train harder than he does, in my mind."

That hard training paid dividends as Dillashaw was able to out-last and wear-down Barao. For the better part of three rounds, however, the fight was closely contested.

Barao found success with his left hook in the first while Dillashaw connected with good, short punches. Neither man was able to score a clean takedown against the other, either.

By the end of the round, however, it was clear that Dillashaw had the faster hands, and was better balanced on his feet, even as he switched stances often. He bloodied the face of Barao and landed the cleaner, more frequent strikes.

The second round began with Dillashaw continuing to snap punches, and then he moved Barao around well in the clinch, though he was unable to score a takedown. In fact, the Brazilian was the first to complete a takedown - of the double leg variet - though Dillashaw got right back to his feet and looked for his own against the fence.

Dillashaw was unable to get the takedown, but he landed hard punches on separation. After he got free, Barao kicked Dillashaw's legs out from under him, before defending another takedown attempt.

Barao landed a hard knee to the head near the end of the round, and referee Herb Dean had to physically stop the two warriors from hitting each other after the horn sounded.

Both men clipped one another with punches in the third round, but Dillashaw contiuned a steady pace of offense as Barao slowed a bit. Notably, Barao threw a slow front kick out and was instantly countered with an overhand right punch to the face for his effort.

As the former champion began to tire more, Dillashaw caught him against the fence and battered Barao with punches to close the round. It appeared as though Barao was saved by the horn.

Dillashaw smelled blood and picked up in the fourth right where he left off in the third - pressing Barao against the cage and landing big punches. The champion connected with several hard straight punches that stiffened up the challenger.

Barao stayed on his feet but mounted no effective defense or offense. Dillashaw teed-off on Barao with punches until the referee wisely stepped in and called a halt to the action.

The stoppage came at 35 seconds of the fourth round. The win is Dillashaw's fourth-straight.

The champion's record improves to 13-2. Barao's stellar record drops to 35-3.