Wales' Nathan Cleverly beat Juergen Braehmer in Germany to claim the WBA 'regular' light-heavyweight title.
Braehmer was pulled out by his corner at the start of the seventh round with a dislocated right elbow.
Cleverly, 29, is the first Welshman to lose and regain a world title at the same weight, although he only holds the WBA's secondary belt.
Russia's Sergey Kovalev, who took the WBO title from Cleverly in 2013, is the WBA's so-called 'super' champion.
Braehmer, 37, was stopped for the first time in a 51-fight career and defeated for only the third time, while Cleverly now has 30 wins from 33 professional fights.
The pair set a frantic pace in the first six rounds in Neubrandenburg, with Cleverly showing discipline and a solid chin as he absorbed some powerful shots from the champion.
However, Cleverly enjoyed some success with body shots and was throwing a far greater number of punches, culminating in a strong sixth round that left Braehmer unable to continue.
"If Braehmer wants a rematch he can have one, but I broke him up. The younger lion won," said Cleverly.
Cleverly had originally been scheduled to face Braehmer in 2011 but the German suffered an eye injury in training.