Costello overcame a significant step up in weight and the toughest opponent he has ever faced to claim victory in the bout at Melbourne’s Docklands.

The 19-year-old triumphed over Nick Themlakas by unanimous points decision in the light middleweight fight after proving too slick from first bell to last.

“I had a higher workrate, I landed cleaner shots and I was just dominating the whole fight,’’ Costello said yesterday.

“I knew this bloke was going to be tough and competitive, but I didn’t think he’d be this tough.

“I hit him with everything I had a few times but he’s got the hardest chin of anyone I’ve ever fought and he wouldn’t go down.

“In pros everyone can fight, everyone has a good chin and at least one good hand.’’

Indeed the main challenge for Costello in the lead-up to the fight appeared to be stepping up to the 68kg weight after fighting the majority of his career in the 63.5kg light welterweight class.

He was forced to make the switch after his opponent for the Victorian light welterweight title fight - scheduled about a week ago - withdrew.

Now that apparent low blow could prove a defining moment in the two-time Victorian and 2007 Australian amateur champion’s career.

“It wasn’t as hard as I thought it would be, actually,’’ he said.

“I’ve been sparring people that weight anyway, so I was sort of used to it.

“I’ll stay in this division now and hover between light welterweight and light middleweight.

“I’ll get a wider range of fighters that way.

“I suppose it could be a good thing that guy pulled out.’’

Costello used to train with Bendigo boxing and Muay Thai guru Frank Pianto, but moved to Echuca with the blessing of his former trainer to further his career.

He will fight in Echuca in five weeks’ time - potentially for the Victorian welterweight title.

In the meantime, Costello will keep a close vigil on diet and hope for the chance to spar with a high-profile Australian boxer as he chases a professional belt.

“I’m hoping to get a title very soon,’’ he said.

“If Danny Green and Anthony Mundine have another fight, hopefully I’ll be able to get in on that (undercard).

“Green trains at the gym I train at sometimes (in Melbourne), so I’m hoping I’ll be able to spar with him soon.’’

Anyone interested in boxing or kickboxing in Bendigo can call Frank Pianto on 0401 306 308.