Marco Antonio Barrera took the World Boxing Council super featherweight title from Erik Morales in an epic battle in Las Vegas on Saturday.
Mexican Barrera won a 12-round majority decision for his second win over compatriot Morales in three meetings since 2000.
Barrera was favoured 115-113 on one card and 115-114 on a second. The third judge scored it 114-114.
The bout was every bit the equal of the classic they fought four years ago.
On that occasion, the two boxers traded more than 1,500 punches before Morales, born in Tijuana, won a split decision.
Two years later Barrera, from Mexico City, came back to win the second fight on a unanimous decision.
The third instalment matched two boxers with no love for each other who are both heroes in their respective corners of Mexico.
At the MGM Grand on Saturday, Barrera - nicknamed The Baby Faced Assassin - was fighting for the first time at 130 pounds and was the stronger fighter in the early rounds.
Morales - known as El Terrible - was bleeding from the nose from the early rounds on and his left eye was swelling by the eighth round.
Both fighters rocked the other with punches and in the final two rounds they fought furiously.
But Barrera had done enough and he held two fingers in the air to signify victory when the decision was announced, while Morales simply stared in disbelief.
"It was the most rewarding fight of my career," said Barrera. "I did this fight to show all boxing fans that this is what boxing is all about."
Morales admitted: "My body didn't respond to what I wanted it to do. I don't know why.
"I felt a little tight early, I couldn't get my jab off. I know I gave away a lot of early
On the undercard, Mexico's Oscar Larios successfully defended his WBC super bantamweight title against Australian Nedal Hussein.
Larios controlled the full 12 rounds and was awarded a unanimous points decision by the judges in Las Vegas 118-110, 119-109 and 120-108.
The Mexican improved his record to 54-3-1 with 35 of those wins inside the distance while Hussein slid to 36-2.
Ivan Calderon remained unbeaten and kept his WBO strawweight title with a straightforward win over Carlos Fajardo.
The Puerto Rican dominated throughout and won a unanimous decision for his 21st victory.
Mexico's Rafael Marquez stopped Colombian Mauricio Pastrana in the eighth round to retain his IBF bantamweight world title.
Pastrana was unable to see from his right eye and his left eye was bloodied as his corner called for a halt.