Frankie Gavin blamed illness for failing to hit top gear in a lop-sided points victory over Young Mutley at the 02 Arena last Saturday night.
The hot Frank Warren prospect from the Midlands dominated a passive opponent in a one-sided affair on the DeGale/Groves undercard.
But he failed to capitalise on his superiority in a fight that lacked great excitement for the big London crowd.
Gavin (now 10-0 as a pro), who said afterwards that he'd been close to pulling out last week, started impressively by pushing back his experienced opponent in the first couple of rounds.
He stepped it up again in the third but appeared to be hurt - perhaps for the first time in his fledgling career - by a Mutley left hook which landed cleanly.
Gavin continued to probe for openings and landing some pretty decent body shots as Mutley seemed unable to move off the back foot.
But as the fight wore on 'Funtime Frankie' struggled to move up a gear and land combinations, and that inability led to a low-key affair.
Young Mutley failed to pose any real questions for Gavin, and seemed content just to survive rather than to try and win the fight.
The final round and the closing bell brought a few boos from the crowd, before Jimmy Lennon Jr announced scores of 118-110 and 119-109 twice for Gavin.
But afterwards the victor admitted that despite staying perfect as a pro and claiming the WBO intercontinental welterweight title, he wasn't at all satisfied.
He told Sky Box Office: "I'm far from happy. No excuses, but I was close to pulling out last week. I was out of the gym for two days. Everyone in the changing room will tell you that I was coughing a lot. I didn't want to let anybody down.
"I wasn't 'ill' ill. I was ill last week and it definitely took something out of me. I didn't feel strong like I did in my last fight."Tags: Frankie Gavin