Having lost his unbeaten record at Sandown last time out, McCain gave the seven-year-old a wind operation but openly admitted he thought it was going to be a big ask for his charge a long way from home on Town Moor.
Champion jockey Brian Hughes is that for a reason, though, and nursed the 13-2 chance into contention approaching the second-last in the Grade Two affair.
Hurricane Bay and Stay Away Fay were tough competition, but Maximilian stuck gamely to his task and prevailed by a length.
He was roared back into the paddock by scores of members of his Owners Group syndicate, a group who have supported McCain well.
McCain is not struck on a Cheltenham bid, however, and Aintree seems more likely.
"I nearly walked away with a circuit to run. He's got that in him, he can switch off," said McCain.
"He's one of those staying hurdlers who races off the bridle and saves plenty for himself.
"If he'd gone clear he'd have probably pulled up, like those good staying hurdlers when he hits the front he thinks he's done enough."
He went on: "He hated the ground at Sandown, he wasn't right afterwards but he was still third in a Grade Two, we've always had a lot of faith in him but he'll never be flash.
"We'll go for a big novice, but I'm not a massive Cheltenham fan. He's a long-term horse and I've not got hundreds of these. Aintree would be first choice, I think.
"He jumps like he'll jump a fence, but I just wonder if he's one of those real staying hurdlers.
"The Owners Group are great, I'm lucky to have a few for them. It's the same wherever they run. It just works."
Tommy's Oscar stamped his class on the MND Association Race For Research Lightning Novices' Chase with a smooth performance.
A Grade Two winner over hurdles, he was just below the very best last season but promised to take high rank over fences.
A win at Carlisle and a second in a hot event at Cheltenham to Banbridge offered plenty of encouragement on that front, but reverting to hurdles for the Fighting Fifth did not quite work out.
Due to a lack of opportunities he was in a limited handicap at Newcastle most recently, conceding lumps of weight to Since Day One, who took him on at levels on this occasion and the tables were well and truly turned.
Harry Fry's favourite Boothill loomed to the front early in the straight but Danny McMenamin was full on confidence on Tommy's Oscar (7-4) and came between horses pulling double.
Two good leaps at the last two fences sealed the deal by five and a half lengths for Ann and Ian Hamilton's star.
"He wants better ground and a flat track. He wasn't giving away loads of weight today, either," said Ian Hamilton.
"He tends to jump right, but didn't do that until the last today when he was in the clear.
"I don't know what we do now, we may have to wait until Aintree. He's not a Cheltenham horse. There's nothing I can see that we can run him in, it's been the case all season which was why he ran at Newcastle giving all that weight.
"Ann and I are getting on, we don't want to be travelling with him to the other end of the country.
"We haven't had a great season, our horses are badly handicapped, but this lad is good."
