Juan Manuel Marquez claimed the WBC super featherweight title with a unanimous decision over fellow Mexican Marco Antonio Barrera in Las Vegas.
Marquez moved up from featherweight to capture Barrera's title
Barrera put Marquez down in the seventh round with a stinging right, only for referee Jay Nady to signal it a slip.
And there was more controversy when the champion was then docked a point for landing a punch with Marquez still kneeling on the canvas.
Marquez recovered and fought hard to take a 116-111 116-111 118-109 verdict.
But three-weight world champion Barerra, 33, was furious with the outcome.
He said: "We fought like true Mexicans but I did the necessary things to win. They were bad judges. I won the fight and I don't know what happened."
Barrera, referring to his point deduction added: "I never connected with the punch because I knew he was down. He hit me four times below the belt and I never said anything."
The explosive fight ended with both men bleeding badly - Barrera from his left eye and Marquez from his right - and both raising their arms in victory.
Marquez, also 33, and an ex-WBA and IBF featherweight champion, admitted that they should meet again to settle the rivalry more conclusively.
"Barrera is a great champion," he said. "He deserves a rematch."