Hughie Fury stayed on course for another world title shot as Christian Hammer retired with a bicep injury after a fiery heavyweight fight in Newcastle.
Fury troubled Hammer with sharp combinations from the opening bell and the German challenger signalled that he could not continue after the fifth round at the Utilita Arena.
The 27-year-old, who became the first man to stop Hammer since his cousin Tyson Fury, is targeting another world title fight after losing on points to Joseph Parker in a battle for the WBO belt in 2017.
Pumping out his jab, Fury probed the defences of Hammer, who smiled defiantly after receiving a thudding right hand in the first round.
Fury unloaded an eye-catching uppercut in the second, while he caught Hammer with a sharp right hook at the end of the third round.
The stubborn resistance of Hammer was tested by a string of clean right hands from Fury in a lively fourth.
A stiff right in response from Hammer sparked a fiery assault from Fury, who pumped out hurtful punches in the fifth, forcing his opponent to signal his retirement.
"I had more gears to offer," Fury told Sky Sports.
"He was getting sick in there. My dad said: 'Keep hitting him with light shots and he'll go'.
"That was only 50 percent of me.
"The stoppage was coming no matter what. You could see Hammer was getting sick of being hit.
"I'm only 27. This is what I love to do - fight!"
Sky Sports Boxing schedule
October 24 - Top Rank in Atlanta
Jamel Herring vs Shakur Stevenson - WBO super-featherweight title
October 31 - Top Rank in New York
Jose Zepeda vs Josue Vargas
November 6 - Top Rank in Las Vegas
Mikaela Mayer vs Maiva Hamadouche - IBF and WBO super-featherweight titles
November 6 - BOXXER in Liverpool
November 20 - BOXXER in London
Richard Riakporhe vs Olanrewaju Durodola
Caroline Dubois professional debut
November 20 - Top Rank in Las Vegas
Terence Crawford vs Shawn Porter - WBO welterweight title
December 11 - BOXXER in Birmingham
December 11 - Top Rank in Las Vegas
Vasiliy Lomachenko vs Richard Commey
December 17 - Top Rank in Montreal
Artur Beterbiev vs Marcus Browne - IBF and WBC light-heavyweight titles
December 18 - Top Rank in Glasgow
Josh Taylor vs Jack Catterall - undisputed super-lightweight title