
The 6ft 9in traveller of Irish descent captured the public’s imagination with his televised win over Dereck Chisora to claim the domestic title in July and was keen to build on that momentum at the famous King’s Hall on Saturday night.
He started with intent, too, ramming the jab and right hand home and bloodying Firtha’s nose badly in the first.
Experienced Firtha turned the tables in the third round by exposing Fury’s vulnerable defence and hurting the Englishman, but the youngster rode it out and fired back.
The 23-year-old regained the upper hand, slamming home slow but heavy hands and forced his opponent to take a count in the fourth round.
Referee John Keane’s stoppage looked untimely in the following round, but Firtha did not seem too upset to be spared further punishment.
The win took Fury’s record to 16 wins, 11 by knockout.
He told Channel 5 afterwards the end had not been premature.
“He was seconds away from being blasted out of there,” said the Briton.
His promoter, Mick Hennessy, declared Fury to be the “most exciting fighter in world boxing” after his win and said his man would return to action on November 12.