Brian Rose was given a baptism of fire on his first step beyond domestic level before stopping Joachim Alcine in the 12th round in Blackpool.
Rose was hoping to put on a show in front of his hometown crowd but his debut for promoters Matchroom did not go as planned against a tricky opponent.
Alcine had held the WBA light-middleweight title but at 37 his best days were thought to be behind him.
But although Rose had the better of the early exchanges he allowed his Canadian opponent back into the fight and it was still to play for going into the final round.
Alcine had been rocked by a right hand late in the 11th and after beginning to get on top suddenly looked the much older man, Rose jumping on him in the corner after another right got home.
A barrage of vicous blows later and the contest was over, much to the relief of those ringside who had worn anxious looks for much of the fight.
The British champion won his Lonsdale belt outright in his previous fight but promoter Eddie Hearn was keen to find out where he stood on an international scale.
Alcine gave him the test he wanted but it was almost a step too far, however in claiming the WBO inter-continental strap the Rose will earn a decent ranking on the back of this.
He looked to assert from the outset and Alcine did not really come alive until after halfway, throwing single shots and looking to tie Rose up as he came in.
The Briton's timing was off with the right hand and bar a sweet left to the body Alcine was rarely troubled until the fight opened up, most worrying in the ninth as the Canadian finally went on the attack.
Rose looked very weary and the bell would have been a welcome sound after Alcine staggered him with a right hand and numerous follow ups that threatened to de-rail the homecoming.
But the 29-year-old weathered the storm and managed to turn the fight around to the delight of the crowd.
"I showed him too much respect but there was a lot of pressure on me tonight," he told Sky Sports. "That next step up obviously told a little bit.
"I caught him with a good shot and just felt I had to keep the pressure on. I probably could have done it earlier but I was conserving a bit of energy and I shouldn't be doing that.
"I never felt tired once but I'm so used to going the distance I've got used to having an easy round. I know I need to get out of that but I know I'm capable of getting a world title."