Jüergen Bräehmer won the WBA light-heavyweight title when he beat Marcus Oliveira on points on Saturday night.
The 35-year-old German, in his second attempt to win a “world” title in the division, won the fight in Neubrandenburg by 117-110 on two cards and 115-112 on the third.
The two fought for the vacant title after Beibut Shumenov of Kazakhstan was promoted to “super champion” earlier this year.
Brähmer lost his previous title bid against former WBA champion Hugo Hernan Garay in November 2008, the second of the two defeats of his career.
"It has been a hard, long year and I was really feeling it in the last round," he said. "He's never been beaten before and it was a really tough fight."
The start of the fight was briefly delayed as Oliveira took a long time coming out of his dressing room, claiming a problem with his gloves, but Brähmer said the American’s tactics had not affected him.
"I didn't want to get involved in all that kindergarten stuff It didn't bother me and you saw what happened."
The previously unbeaten Oliveira, 34, with promoter Don King in his corner, suffered his first defeat in 27 professional fights having arrived with a record of 20 knockouts in 25 wins and one draw.
"I just kept trying to hit him with a big shot, but he's a smart boxer and it didn't come off," said the disappointed Oliveira.
In the co-feature, heavyweight contender Kubrat Pulev (19-0, 10KOs) scored multiple knockdowns on dangerous puncher Joey Abell (29-7, 28KOs) to secure a fourth round TKO.